1485 lines
77 KiB
Plaintext
1485 lines
77 KiB
Plaintext
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C e l l u l a r T e l e p h o n y I I
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by
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B r i a n O b l i v i o n
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A -=Restricted -=Data -=Transmission
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In the last issue we discussed the history of cellular telephony,
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monitoring techniques, and a brief description of its predecessors.
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In this issue I'll describe the call processing sequences for land-
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originated and mobile-originated calls, as well as the signaling
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formats for these processes. I apologize for the bulk of information
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but I feel it is important for anyone who is interested in how the
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network communicates. Please realize that there was very little I
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could add to such a cut and dried topic, and that most is taken
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verbatim from Industry standards, with comments and addendums salt
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and peppered throughout.
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Call-Processing Sequences
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Call-Processing Swquence for Land-Originated Calls
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MTSO Cell Site Mobile Unit
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------------------------------------------------------------------------------
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1--Transmits setup channel
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data on paging channel
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2 ----------------------------Scans and locks on
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paging channel
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Receives incoming call --- 3
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and performs translations
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Sends paging message ----- 4
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to cell site
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5 -- Reformats paging
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message
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6 -- Sends paging message
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to mobile unit via
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paging channel
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7 ----------------------------Detects Page
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8 ----------------------------Scans and locks on
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access channel
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9 ----------------------------Seizes setup channel
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10 ----------------------------Aquires sync
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11 ----------------------------Sends service request
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12 -- Reformats service request
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13 -- Performs dirctional locate
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14 -- Sends service request to
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MTSO
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Selects voice channel --- 15
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Sends tx-on command to -- 16
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cell site
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17 -- Reformats channel designation
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message
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18 -- Sends channel designation
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message to mobile unit via
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access channel
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19 -----------------------------Tunes to voice
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channel
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20 -----------------------------Transponds SAT
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21 -- Detects SAT
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22 -- Puts on-hook on trunk
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Detects off-hook -------- 23
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Sends alert order ------- 24
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25 -- Reformats alert order
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26 -- Sends alert order to
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mobile unit via blank-
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and-burst on voice channel
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27 -----------------------------Alerts User
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28 -----------------------------Sends 10-kHz tone
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29 -- Detects 10-kHz tone
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30 -- Puts on-hook on trunk
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Detects on-hook --------- 31
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Provides audible ring --- 32
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33 -- Detects absence of 10-kHz
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tone
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34 -- Puts off-hook on trunk
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Detects off-hook -------- 35
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Removes audible ring ---- 36
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and completes connection
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Time
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Call-Processing Sequence for Mobile-Originated Calls
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MTSO Cell Site Mobile Unit
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------------------------------------------------------------------------------
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1 -- Transmits setup channel
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data on paging channel
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2 --------------------------- Scans and locks-on
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paging channel
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3 --------------------------- User initiates call
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4 --------------------------- Scans and locks-on
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access channel
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5 --------------------------- Seizes setup channel
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6 --------------------------- Aquires sync
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7 --------------------------- Sends service request
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8 -- Reformats service request
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9 -- Performs directional Locate
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10 -- Sends service request to
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MTSO
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Selects voice channel ---- 11
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Sends tx-on command to --- 12
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cell site
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13 -- Reformats channel
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designation message
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14 -- Sends channel designation
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message to mobile unit via
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access channel
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15 --------------------------- Tunes to voice
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channel
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16 --------------------------- Transponds SAT
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17 -- Detects SAT
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18 -- Puts off-hook on trunk
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Detects off-hook --------- 19
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Completes call through --- 20
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network
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Time
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Let me review the frequency allocation for Wireline and non-Wireline
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systems. Remember that the Wireline service is usually provided by
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the area's Telephone Company, in my area that company is NYNEX. The
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non-Wireline companies are usually operated by other carriers foreign
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to the area, in my area we are serviced by Cellular One (which is owned
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by Southwestern Bell). Each company has its one slice of the electro-
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magnetic spectrum. The coverage is not continuous, remember that there
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are also 800 MHz trunked business systems that also operate in this
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bandwidth. Voice channels are 30 KHz apart and the Data channels are
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10 KHz apart.
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Frequency Range Use
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----------------------------------------------------------------------
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870.000 - 879.360 Cellular One (mobile input 825.000 - 834.360)
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880.650 - 890.000 NYNEX (mobile input 835.650 - 845.500)
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890.000 - 891.500 Cellular One (mobile input 845.000 - 846.500)
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891.500 - 894.000 NYNEX (mobile input 846.500 - 849.000)
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879.390 - 879.990 Cellular One (data)
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880.020 - 880.620 NYNEX (data)
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The data streams are encoded NRZ (Non-return-to-zero) binary ones
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and zeroes are now zero-to-one and one-to-zero transistions respect-
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ivly. This is so the wideband data can modulate the transmitter
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via binary frequency shift keying, and ones and zeroes into the
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modulator MUST now be equivalent to nominal peak frequency deviations
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of 8 KHz above and below the carrier frequency.
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PUTTING IT ALL TOGETHER - Signaling on the Control Channels
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The following information will be invaluable to the hobbiest that
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is monitoring cellular telephones via a scanner and can access
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control channel signals. All information released below is
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EIA/TIA - FCC standard. There are a lot of differences between
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cellular phones, but all phones must interface into the mobile
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network and talk fluently between each other and cell sites.
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Therefore, the call processing and digital signaling techniques are
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uniform throughout the industry.
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MOBILE CALL PROCESSING
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Calling:
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Initially, the land station transmits the first part of its SID
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to a mobile monitoring some control channel, followed by the number
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of paging channels, an ESN request, then mobile registration, which
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will either be set to 0 or 1. When registration is set to one, the
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mobile will transmit both MIN1 and MIN2 during system access, another
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1 for discontinuous (DTX) transmissions, read control-filler (RCF)
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should be set to 1, and access functions (if combined with paging
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operations) require field setting to 1, otherwise CPA (combined paging
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access) goes to 0.
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Receiving:
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As the mobile enters the Scan Dedicated Control Channels Task, it
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must examine signal strengths of each dedicated control channel
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assigned to System A if enabled. Otherwise System B control channels
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are checked.
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The values assigned in the NAWC (Number of Additional Words
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Coming) system parameter overhead message train will determine for
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the moblie if all intended information has been received. An EDN
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field is used as a crosscheck, and control-filler messages are not
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to be counted as part of the message. Should a correct BCH code
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be received along with a nonrecognizable overhead message, it must
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be part of the NAWC count train but the equivalent should not try
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and execute the instructions.
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Under normal circumstances, mobiles are to tune to the strongest
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dedicated control channel, receive a system parameter transmission,
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and, within 3 seconds, set up the following:
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o Set SID's 14 most significant bits to SID1 field value.
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o Set SID's least significant bit to 1, if serving system status
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enables, or to zero if not.
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o Set paging channels N to 1 plus the value of N-1 field.
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o Set paging channel FIRSTCHP as follows:
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If SIDs = SIDp then FIRSTCHPs = FIRSTCHPp (which is
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an 11-bit paging channel).
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If SIDs = SIDp and serving system is enabled, set
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FIRSTCHPs to initial dedicated channel for system
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B.
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If SIDs = SIDp and serving system is disabled, set
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FIRSTCHPs to first dedicated control channel for
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system B.
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o Set LASTCHPs to falue of FIRSTCHPs + Ns -1.
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o Should the moblie come equipped for autonomous registration, it
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must:
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o Set registragion increment (REGINCRs) to its 450 default
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value.
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o Set registration ID status to enabled.
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I know that was a little arcane sounding but it's the best you can
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do with specifications. Data is data, there is no way to spruce it
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up. From here on out a mobile must begin the Paging Channel Selection
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Task. If this cannot be completed on the strongest dedicated
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channel, the second strongest dedicated channel may be accessed and
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the three second interval commenced again. Incomplete results should
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result in a serving system status check and an enabled or disabled
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state reversed, permitting the moblie to begin the Scan Dedicated
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control Channels Task when channel signal strengths are once more
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examined.
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Custom local operations for mobiles may be sent and include roaming
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mobiles whose home systems are group members. A new access channel
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may be transmitted with a new access field set to the initial access
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channel. Autonomously registered mobiles may increment their next
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registered ID by some fixed value, but the global action message
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must have its REGINCR field adequately set. Also, so that all
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mobiles will enter the Initialization Task and scan dedicated
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control channels, a RESCAN global action message must be transmitted.
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Moblie stations may be required to read a control-filler message
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before accessing any system on a reverse control channel.
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System access for mobiles is sent on a forward control channel in
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the following manner. Digital Color Code (DCC) identifies the land
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station. Control Moblie Attenuation Code (CMAC) is included in the
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control-filler message for moblie power level transmitter adjustment
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before accessing any system on a reverse control channel. The WFOM
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Wait for Overhead Message field must register 0 before the moblie
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accesses a system on a reverse control channel. When moblies are
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assigned to one or more of the 16 overload classes are not to access
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organizations on a reverse control channel, an overload control message
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is carried with the system parameter overhead message overload class
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fields are set to zero among the restricted number, and the remainder
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set to 1. Busy-to-idle status (BIS) access parameters go to zero when
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mobiles are prevented from checking on the reverse control channel and
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the message must be added to the overhead. When mobiles can't use the
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reverse control channel for seizure messages attemps or busy signals,
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access attempt parameters must also be included in the overhead. And
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when a land station receives a seizure precursor matching its digital
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color code with 1 or no bit errors, busy idle bits signals on the
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forward control channel must be set to busy within 1.2 milliseconds
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from the time of the last bit seizure. Busy-idle bit then must remain
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busy until a minimum of 30 msec following the final bit of the last
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word of the message has been received, or a total of 175 msec has
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elapsed.
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Channel Confirmation
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Mobiles are to monitor station control messages for orders and
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respond to both audio and local control orders even though land
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stations are not required to reply. MIN bits must be matched.
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Thereafter, the System Access Task is entered with a page response,
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as above, and an access timer started.
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This time runs as follows:
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o 12 seconds for an origination
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o 6 seconds for page response
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o 6 seconds for an order response
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o 6 seconds for a registration
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The last try code is then set to zero, and the equipment begins the
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Scan Access Channels Task to find two channels with the strongest
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signals which it tunes and enters the Retrieve Access Attempts
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Parameters Task.
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This is where both maximum numbers of seizure attempts and busy
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signals are each set to 10. A read control-filler bit (RCF) will
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then be checked: if the RCF equals zero, the mobile then reads a
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control-filler message, sets DCC and WFOM (wait for overhead message
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train before reverse control channel access) to the proper fields
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and sets the proper fields and sets the appropriate power level.
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Should neither the DCC field nor the control-filler message be
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received and access time has expired, the mobile station goes to
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Serving System Determination Task. But within the allowed access
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time, the mobile station enters the Alternate Access Channel Task.
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BIS is then set to 1 and the WFOM bit is checked. If WFOM equals 1,
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the station enters the Update Overhead Infromation Task; if WFOM
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equals 0, a random delay wait is required of 0 to 200 msec, +/- 1
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msec. Then, the station enters the Seize Reverse Control Channel
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Task.
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Service Requesting is next. This task requires that the mobile
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continue to send is message to the land station according to the
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following instructions:
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o Word A is required at all times.
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o Word B has to be sent if last try access LT equals 1 or
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if E requires MIN1 and/or MIN2, and the ROAM status is
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disabled, or if the station has been paged with a 2-word
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control message.
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o Word C is transmitted with S (serial number) being 1
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o Word D required if the access is an origination
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o Word E transmitted when the access is an origination and
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between 9 and 16 digits are dialed. When the mobile has
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transmitted its complete message, an unmodulated carrier is
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required for another 25 milliseconds before carrier turnoff.
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After words A through E have been sent, the next mobile task
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depends on the type of access.
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Order confirmation requires entry into the Serving System Determination
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Task.
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Origination means entry into the Await Message Task.
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Page response, is the same as Origination.
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Registration requires Await Registration Confirmation, which
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must be completed within 5 seconds or registration failure follows.
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The same is true for Await Message since an incomplete task in 5
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seconds sends the mobile into the Serving System Determination Task.
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Origination or Page response requires mobile update of parameters
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delivered in the message. If R equals 1, the mobile enters the
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Autonomous Registration Task, otherwise, it goes to the Initial
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Voice Channel Confirmation Task. Origination access may be either
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an intercept or reorder, and in these instances, mobiles enter the
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Serving System Determination Task. The same holds true for a page
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response access. But if access is an origination and the user
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terminates his call during this task, the call has to be released
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on a voice channel and not control channel.
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If a mobile staion is equipped for Directed Retry and if a new
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message is received before all four words of the directed retry
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message, it must go to the Serving System Determination Task. There
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the last try code (LT) must be set according to the ORDQ (order
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qualifier) field of the message as follows:
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If 000, LT sets to 0
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If 0001, LT sets to 1
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Thereafter, the mobile clears the list of control channels to be
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scanned in processing Directed Retry (CCLIST) and looks at each
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CHANPOS (channel postition) field contained in message words three
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and four. For nonzeor CHANPOS field, the mobile calculates a cor-
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responding channel number by adding CHANPOS to FIRSTCHA minus one.
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Afterwards, the mobile has then to determine if each channel number
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is within the set designated for cellular systems. A true answer
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requires adding this/these channel(s) to the CCLIST.
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Awaiting Answers
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Here, an alert timer is set for 65 seconds (0 to +20 percent). During
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this period the following events may take place:
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o Should time expire, the mobile turns its transmitter off and
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enters the Serving System Determination Task.
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o An answer requires signaling tone turnoff and Conversation
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Task entry.
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o If any of the messages listed hereafter are received within
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100 milliseconds, the mobile must compair SCC digits that
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identify stored and proper SAT frequencies for the station to
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the PSCC (present SAT color code). If not equivalent, the
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order is ignored. If correct, then the following actions
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taken for each order:
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Handoff: Signaling extinguished for 500 msec, signal tone
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off, transmitter off, power lever adjusted, new
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channel tuned, new SAT, new SCC field, transmitter
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on, fade timer reset, and signaling tone on. Wait
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for an answer.
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Alert: Reset alert timer for 65 seconds and stay in
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Waiting for Answer Task.
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Stop Alert: Extinguish signaling tone and enter Waiting for
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Order Task.
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Release: Signaling tone off, wait 500 msec, then enter
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Release Task.
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Audit: Confirm message to land station, then stay in
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Waiting for Answer Task.
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Maintenance: Reset alert timer for 65 seconds and remain in
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Waiting for Answer Task.
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Change Power: Adjust transmitter to power level required and
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send confirmation to land station. Remain in
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Waiting for Answer Task.
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Local Control: If local control is enabled and order received,
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examine LC field and determine action.
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Orders other than the above for this type of action
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are ignored.
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Conversation
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In this mode, a release-delay timer is set for 500 mSec. If Termin-
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ation is enabled, the mobile sets termination status to disabled and
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waits 500 mSec before entering Release Task. The following actions
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may then execute:
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o Upon call termination, the release delay timer has to be checked.
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If time has expired, the Release Task is entered; if not expired,
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the mobile must wait until expiration and then enter Release Task.
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o Upon user requested flash, signaling tone turned on for 400 mSec.
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But should a valid order tone be received during this interval,
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the flash is immediately terminated and the order processed. The
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flash, of course, is not then valid.
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o Upon receipt of the following listed orders and within 100 mSec,
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the mobile must compare SCC with PSCC, and the order is ignored
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if the two are not equal. But if they are the same, the following
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can occur:
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Handoff: Signaling tone on for 50 mSec, then off, trans-
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mitter off, power level adjusted, new channel tuned,
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adjust new SAT, set SCC to SCC field message value,
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transmitter on, fade timer reset, remain in
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Conversation Task.
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Send Called Address: Upon receipt within 10 seconds of last valid flash,
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called address sent to land station. Mobile remains
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in Conversation Task. Otherwise, remain in Conver-
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sation Task.
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Alert: Turn on signaling tone, wait 500 mSec, then enter
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Waiting for Answer Task.
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Release: Check release delay timer. If time expired, mobile
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enters Release Task; but if timer has not finished,
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then mobile must wait and then enter Release Task
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when time has expired.
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Audit: Order confirmation sent to land station while
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remaining in Conversation Task.
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Maintenance: Signaling tone on, wait 500 mSec, then enter Waiting
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for Answer Task.
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Change Power: Adjust transmitter to power level required by order
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qualification code and send confirmation to land
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station. Remain in Conversation Task.
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Local Control: If local control in enabled and local control order
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received, the LC field is to be checked for subse-
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quent action and confirmation.
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Orders other than the above for this type of action are ignored.
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Release
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In the release mode the following steps are required:
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o Signaling tone sent for 1.8 sec. If flash in transmission when
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signaling tone begun, it must be continued and timing bridged so
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that action stops within 1.8 sec.
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o Stop signaling tone.
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o Turn off transmitter.
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o The mobile staion then enters the Serving System Deter-
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mination Task.
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The above is the Cellular System Mobile/Land Station Compatibility
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Specification. The following shall be Signaling Formats which are
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also found in the above document. I converted all these tables by
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HAND into ASCII so appreciate them. It wasn't the easiest thing to
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do. But I must say, I definately understand the entire cellular
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operation format.
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There are two types of continuous wideband data stream transmissions.
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One is the Forward Control Channel which is sent from the land station
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to the mobile. The other is the Reverse Control Channel, which is
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sent from the mobile to the land station. Each data stream runs at a
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rate of 10 kilobit/sec, +/- 1 bit/sec rate. The formats for each of
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the channels follow.
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- Forward Control Channel
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The forward control channel consists of three discrete information
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streams. They are called stream A, stream B and the busy-idle
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stream. All three streams are multiplexed together. Messages to
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mobile stations with the least significant bit of thier MIN number
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equal to "0" are sent on stream A, and those with a "1" are sent
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on stream B.
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The busy-idle stream contains busy-idle bits, which are used to
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indicate the status of the reverse control channel. If the busy-idle
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|
bit = "0" the reverse control channel is busy, if it equals "1"
|
|
it is idle. The busy-idle bit is located at the beginning of each
|
|
dotting sequence, word sync sequence, at the beginning of the first
|
|
repeat of word A and after every 10 message bits thereafter.
|
|
|
|
Mobile stations achieve synchronization with the incoming data via
|
|
a 10 bit dotting sequence (1010101010) and an 11 bit word sync
|
|
sequence (11100010010). Each word contains 40 bits, including parity
|
|
and is repeated 5 times after which it is then refered to as a
|
|
"block". For a multiword message, the second word block and subsequent
|
|
word blocks are formed the same as the first word block including the
|
|
dotting and sync sequences. A "word" is formed when the 28 content
|
|
bits are encoded into a (40, 28; 5) BCH (Bose-Chaudhuri-Hocquenghem)
|
|
code. The left-most bit shall be designated the most-signifigant bit.
|
|
|
|
The Generator polynominal for the (40, 28;5) BCH code is:
|
|
|
|
12 10 8 5 4 3 0
|
|
G (X) = X + X + X + X + X + X + X
|
|
B
|
|
|
|
Each FOCC message can consist of one or more words. Messaging trans-
|
|
mitted over the forward control channel are:
|
|
|
|
- Mobile station control message
|
|
- Overhead message
|
|
- control-filler message
|
|
|
|
Control-filler messages may be inserted between messages and
|
|
between word blocks of a multiword message.
|
|
|
|
Message Formats: Found on either stream A or B
|
|
|
|
- Mobile Station Control Message
|
|
|
|
The mobile station control message can consist of one, two, or four
|
|
words.
|
|
|
|
Word 1 (abbreviated address word)
|
|
|
|
+--------+-------+---------------------------------------+-----------+
|
|
| T t | | | |
|
|
| 1 2 | DCC | Moblie Identification Number 1 | P |
|
|
| | | 23-0 | |
|
|
+--------+-------+---------------------------------------+-----------+
|
|
bits: 2 2 24 12
|
|
|
|
Word 2 (Extended Address Word)
|
|
|
|
|
|
+------+-----+-----------+------+--------+-------+----------+-----+
|
|
| T T |SCC =| | RSVD | LOCAL | CRDQ | ORDER | |
|
|
| 1 2| 11 | MIN2 | = 0 | | | | |
|
|
| = +-----+ 3-24 +------+-----+--+-------+----------| P |
|
|
| 10 |SCC =| | VMAC | CHAN | |
|
|
| | 11 | | | | |
|
|
+------+-----+-----------+------------+---------------------+-----+
|
|
2 2 10 3 11 12
|
|
|
|
|
|
Word 3 (First Directed-Retry Word)
|
|
|
|
+------+-----+-----------+-----------+-----------+-------+--------+
|
|
| T T | SCC | | | | RSVD | |
|
|
| 1 2| = | CHANPOS | CHANPOS | CHANPOS | = | |
|
|
| = | | | | | 000 | P |
|
|
| 10 | 11 | | | | | |
|
|
+------+-----+-----------+-----------+-----------+-------+--------+
|
|
2 2 7 7 7 3 12
|
|
|
|
|
|
Word 4 (Second Directed-Retry Word)
|
|
|
|
+------+-----+-----------+-----------+-----------+-------+--------+
|
|
| T T | SCC | | | | RSVD | |
|
|
| 1 2| = | CHANPOS | CHANPOS | CHANPOS | = | |
|
|
| = | | | | | 000 | P |
|
|
| 10 | 11 | | | | | |
|
|
+------+-----+-----------+-----------+-----------+-------+--------+
|
|
2 2 7 7 7 3 12
|
|
|
|
|
|
The interpretation of the data fields:
|
|
|
|
T T - Type field. If only Word 1 is send, set to 00 in Word 1.
|
|
1 2 If a multiple-word message is sent, set to 01 in Word 1
|
|
and set to 10 in each additional word.
|
|
|
|
DCC - Digital Color Code field
|
|
|
|
MIN1 - First part of the mobile identification number field
|
|
MIN2 - Second part of the mobile identification number field
|
|
SCC - SAT color code (discussed previously)
|
|
ORDER - Order field. Identifies the order type (see table below)
|
|
ORDQ - Order qualifier field. Qualifies the order to a specific
|
|
action
|
|
LOCAL - Local control field. This field is specific to each system.
|
|
The ORDER field must be set to local control for this field
|
|
to be interpreted.
|
|
VMAC - Voice Mobile Attenuation Code field. Indicates the mobile
|
|
station power level associated with the designated voice
|
|
channel.
|
|
CHAN - Channel number field. Indicates the designated voice channel.
|
|
CHANPOS- CHANnel POSition field. Indicates the postiion of a control
|
|
channel relative to the first access channel (FIRSTCHA).
|
|
RSVD - Reserved for future use, all bits must be set as indicated.
|
|
P - Parity field.
|
|
|
|
|
|
Coded Digital Color Code
|
|
+--------------------------------------------+
|
|
| Received DCC 7-bit Coded DCC |
|
|
| 00 0000000 |
|
|
| 01 0011111 |
|
|
| 10 1100011 |
|
|
| 11 1111100 |
|
|
+--------------------------------------------+
|
|
|
|
|
|
Order and Order Qualification Codes
|
|
|
|
+-------+-------------+-----------------------------------------------------+
|
|
| Order | Order | |
|
|
| Code |Qualification| Function |
|
|
| | Code | |
|
|
+-------+-------------------------------------------------------------------+
|
|
| 00000 000 page (or origination) |
|
|
| 00001 000 alert |
|
|
| 00011 000 release |
|
|
| 00100 000 reorder |
|
|
| 00110 000 stop alert |
|
|
| 00111 000 audit |
|
|
| 01000 000 send called-address |
|
|
| 01001 000 intercept |
|
|
| 01010 000 maintenance |
|
|
| |
|
|
| 01011 000 charge power to power level 0 |
|
|
| 01011 001 charge power to power level 1 |
|
|
| 01011 010 charge power to power level 2 |
|
|
| 01011 011 charge power to power level 3 |
|
|
| 01011 100 charge power to power level 4 |
|
|
| 01011 101 charge power to power level 5 |
|
|
| 01011 110 charge power to power level 6 |
|
|
| 01011 111 charge power to power level 7 |
|
|
| |
|
|
| 01100 000 directed retry - not last try |
|
|
| 01100 001 directed retry - last try |
|
|
| |
|
|
| 01101 000 non-autonomous registration - don't reveal location |
|
|
| 01101 001 non-autonomous registration - make location known |
|
|
| 01101 010 autonoumous registration - don't reveal location |
|
|
| 01101 011 autonoumous registration - make location known |
|
|
| |
|
|
| 11110 000 local control |
|
|
| |
|
|
| All other codes are reserved |
|
|
| |
|
|
+---------------------------------------------------------------------------+
|
|
|
|
|
|
Forward Voice Channel
|
|
|
|
The forward voice channel (FVC) is a wideband data stream sent by the
|
|
land station to the mobile station. This data stream must be gen-
|
|
erated at a 10 kilobit/Sec +/- .1 bit/Sec rate. The Forward Voice
|
|
Channel format follows:
|
|
|
|
+-----------+------+--------+-----+------+--------+-----+------+------
|
|
|| | | Repeat | | | Repeat | | |
|
|
|| | word | | | word | | | word |
|
|
|| Dotting | sync | 1 of | dot | sync | 2 of | dot | sync | ...
|
|
|| | | | | | | | |
|
|
|| | | Word | | | Word | | |
|
|
+-----------+------+--------+-----+------+--------+-----+------+------
|
|
101 11 40 37 11 40 37 11
|
|
|
|
-----+--------+-----+------+--------+-----+------+--------+
|
|
| Repeat | | | Repeat | | | Repeat ||
|
|
| | | word | | | word | ||
|
|
| 9 of | dot | sync | 10 of | dot | sync | 11 of ||
|
|
| | | | | | | ||
|
|
| Word | | | Word | | | Word ||
|
|
-----+--------+-----+------+--------+-----+------+--------+
|
|
40 37 11 40 37 11 40
|
|
|
|
|
|
A 37-bit dotting sequence and an 11-bit word sync sequence are sent
|
|
to permit mobile staions to achieve synchronization with the incom-
|
|
ming data, except at the first repeat of the word, where the 101-bit
|
|
dotting sequence is used. Each word contains 40 bits, including
|
|
parity, and is repeated eleven times together with the 37-bit dotting
|
|
and 11-bit word sync; it is then refered to as a word block. A word
|
|
block is formed by encoded the 28 content bits into a (40, 28) BCH
|
|
code that has a distance of 5 (40, 28; 5). The left-most bit (as
|
|
always) is designated the most-significant bit. The 28 most-
|
|
significant bits of the 40-bit field shall be the content bits. The
|
|
generator polynominal is the same as that used for the forward
|
|
control channel.
|
|
|
|
The mobile station control message is the only message transmitted
|
|
over the forward voice channel. The mobile staion control message
|
|
consists of one word.
|
|
|
|
|
|
Mobile Sation Control Message:
|
|
|
|
+-------+-------+------+-----------+-------+------+-------+------+
|
|
| T T | SCC = | | RSVD = | LOCAL | ORDQ | ORDER | |
|
|
| 1 2 | 11 | | 000 ... 0 | | | | |
|
|
| = +-------| PSCC +-----------+-------+------+-------+ P |
|
|
| | SCC = | | RSVD = | VMAC | CHANNEL | |
|
|
| 10 | 11 | | 000 ... 0 | | | |
|
|
+-------+-------+------+-----------+-------+--------------+------+
|
|
2 2 2 8 3 11 12
|
|
|
|
Interpretation of the data fields:
|
|
|
|
T T - Type field. Set to '10'.
|
|
1 2
|
|
|
|
SCC - SAT color code for new channel (see SCC table)
|
|
PSCC - Present SAT color code. Indicates the SAT color code
|
|
associated with the present channel.
|
|
ORDER - Order field. Identifies the order type. (see Order table)
|
|
ORDQ - Order qualifier field. Qualifies the order to a specific
|
|
action (see Order table)
|
|
LOCAL - Local Control field. Thsi field is specific to each system.
|
|
The ORDER field must be set to local control (see Order table)
|
|
for this field to be interpreted.
|
|
VMAC - Voice mobile attenuation code field. Indicates the mobile
|
|
station power level associated with the designated voice
|
|
channel.
|
|
RSVD - Reserved for future use; all bits must be set as indicated.
|
|
P - Parity field.
|
|
|
|
|
|
|
|
|
|
Reverse Control Channel
|
|
|
|
The Reverse Control Channel (RECC) is a wideband data stream sent
|
|
from the moblie station to the land station. This data stream runs
|
|
at a rate of 10 kilobit/sec, +/- 1 bit/sec rate. The format of the
|
|
RECC data stream follows:
|
|
|
|
+---------+------+-------+------------+-------------+-----------+-----
|
|
| Dotting | Word | Coded | first word | Second word | Third word|
|
|
| | sync | DCC | repeated | repeated | repeated | ...
|
|
| | | | 5 times | 5 times | 5 times |
|
|
+---------+------+-------+------------+-------------+-----------+-----
|
|
bits: 30 11 7 240 240 240
|
|
|
|
|
|
Dotting = 01010101...010101
|
|
Word sync = 11100010010
|
|
|
|
|
|
All messages begin with the RECC seizure precursor with is composed
|
|
of a 30 bit dotting sequence (1010...101), and 11 bit word sync
|
|
sequence (11100010010), and the coded digital color code.
|
|
|
|
Each word contains 48 bits, including parity, and is repeated five
|
|
times after which it is refered to as a word block. A word is
|
|
formed by encoding 36 content bits into a (48, 36) BCH code that has
|
|
a distance of 5, (48 36; 5). The left most bit shall be designated
|
|
the most-significant bit. The 36 most-significant bits of the 48 bit
|
|
field shall be the content bits.
|
|
|
|
The generator polynomial for the code is the same for the (40,28;5)
|
|
code used on the forward channel.
|
|
|
|
Each Reverse Control Channel message can consist of one of the five
|
|
words. The types of messages to be transmitted over the reverse
|
|
control channel are as follows:
|
|
|
|
o Page Response Message
|
|
o Origination Message
|
|
o Order Confirmation Message
|
|
o Order Message
|
|
|
|
These messages are made up of combination of the following five words:
|
|
|
|
Word A - Abbreviated Address Word
|
|
|
|
+---+------+---+---+---+------+---+-----------------------------------+---+
|
|
| F | | | | | RSVD | S | | |
|
|
| | | | | | | | | |
|
|
| = | NAWC | T | S | E | = | C | MIN 1 | P |
|
|
| | | | | | | | 23 - 0 | |
|
|
| 1 | | | | | 0 | M | | |
|
|
+---+------+---+---+---+------+---+-----------------------------------+---+
|
|
1 3 1 1 1 1 4 24 12
|
|
|
|
|
|
Word B - Extended Address Word
|
|
|
|
+---+------+-------+------+-------+----+------+-----------------------+---+
|
|
| F | | | | | | RSVD | | |
|
|
| | | | | | | | | |
|
|
| = | NAWC | LOCAL | ORDQ | LOCAL | LT | = | MIN 2 | P |
|
|
| | | | | | | | 33-24 | |
|
|
| 0 | | | | | | 00..0| | |
|
|
+---+------+-------+------+-------+----+------+-----------------------+---+
|
|
1 3 5 3 5 1 8 10 12
|
|
|
|
|
|
Word C - Electronic Serial Number Word
|
|
|
|
+---+--------+--------------------------------------+---------------+
|
|
| F | | | |
|
|
| | | | |
|
|
| = | NAWC | SERIAL (ESN) | P |
|
|
| | | | |
|
|
| 1 | | | |
|
|
+---+--------+--------------------------------------+---------------+
|
|
1 3 32 12
|
|
|
|
|
|
Word D - First Word of the Called-Address
|
|
|
|
+---+------+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
| F | | 1 st | 2 nd | | | | | 7th | 8th | |
|
|
| | | | | | | | | | | |
|
|
| = | NAWC | DIGIT | DIGIT | ... | ... | ... | ... | DIGIT | DIGIT | P |
|
|
| | | | | | | | | | | |
|
|
| 1 | | | | | | | | | | |
|
|
+---+------+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
1 3 4 4 4 4 4 4 4 4 12
|
|
|
|
|
|
Word E - Second Word of the Called-Address
|
|
|
|
+---+------+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
| F | NAWC | 9 th | 10th | | | | | 15th | 16th | |
|
|
| | | | | | | | | | | |
|
|
| = | = | DIGIT | DIGIT | ... | ... | ... | ... | DIGIT | DIGIT | P |
|
|
| | | | | | | | | | | |
|
|
| 0 | 000 | | | | | | | | | |
|
|
+---+------+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
1 3 4 4 4 4 4 4 4 4 12
|
|
|
|
|
|
The interpretation of the data fields is as follows:
|
|
|
|
F - First word indication field. Set to '1' in first word and '0'
|
|
in subsequent words.
|
|
|
|
NAWC - Number of additional words coming field.
|
|
T - T field. Set to '1' to identify the message as an origination
|
|
or an order; set to '0' to identify the message as an order
|
|
response or page response.
|
|
S - Send serial number word. If the serial number word is sent,
|
|
set to '1'; if the serial number word is not sent, set
|
|
to '0'.
|
|
SCM - The station class mark field
|
|
ORDER - Order field. Identifies the order type.
|
|
ORDQ - Order qualifier field. Qualifies the order confirmation to a
|
|
specific action.
|
|
LOCAL - Local control field. This field is specific to each system.
|
|
The ORDER field must be set to locate control for this field
|
|
to be interpreted.
|
|
LT - Last-try code field.
|
|
MIN1 - Mobile Identification number field part one.
|
|
MIN2 - Mobile Identification number field part two.
|
|
SERIAL - Electronic Serial Number field. Identifies the serial number
|
|
of the mobile station.
|
|
DIGIT - Digit field (see table below)
|
|
RSVD - Reserved for future use; all bits must be set as indicated.
|
|
P - Parity field.
|
|
|
|
|
|
Called-address Digit Codes
|
|
+------------------------------------------------------------------------+
|
|
| Digit Code Digit Code |
|
|
| |
|
|
| 1 0001 7 0111 |
|
|
| 2 0010 8 1000 |
|
|
| 3 0011 9 1001 |
|
|
| 4 0100 0 1010 |
|
|
| 5 0101 * 1011 |
|
|
| 6 0110 # 1100 |
|
|
| Null 0000 |
|
|
| |
|
|
| NOTE: |
|
|
| 1. The digit 0 is encoded as binary 10, not binary zero. |
|
|
| 2. The code 0000 is the null code, indicated no digit present |
|
|
| 3. All other four-bit sequences are reserved, and must not be |
|
|
| transmitted. |
|
|
| |
|
|
+------------------------------------------------------------------------+
|
|
|
|
|
|
Examples of encoding called-address information into the called-
|
|
address words follow:
|
|
|
|
If the number 2# is entered, the word is as follows:
|
|
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
| NOTE | 0010 | 1100 | 0000 | 0000 | 0000 | 0000 | 0000 | 0000 | P |
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
|
|
If the number 13792640 is entered, the word is as follows:
|
|
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
| NOTE | 0001 | 0011 | 0111 | 1001 | 0010 | 0110 | 0100 | 1010 | P |
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
|
|
As you can see the numbers are coded into four bits and inserted
|
|
sequentialy into the train. Notice that when the number is longer
|
|
than 8 numbers it is broken into two different Words.
|
|
|
|
If the number 6178680300 is entered, the words are as follows:
|
|
|
|
Word D - First Word of the Called-Address
|
|
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
| NOTE | 0110 | 0001 | 0111 | 1000 | 0110 | 1000 | 1010 | 1010 | P |
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
4 4 4 4 4 4 4 4 4 12
|
|
|
|
Word E - Second Word of the Called-Address
|
|
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
| NOTE | 0010 | 1010 | 1010 | 0000 | 0000 | 0000 | 0000 | 0000 | P |
|
|
+------+------+------+------+------+------+------+------+------+---------+
|
|
4 4 4 4 4 4 4 4 4 12
|
|
|
|
NOTE = four bits which depend on the type of message
|
|
|
|
|
|
|
|
Reverse Voice Channel
|
|
|
|
The reverse voice channel (RVC) is a wideband data stream sent from
|
|
the mobile station to the land station. This data stream must be
|
|
generated at a 10 kilobit/second +/- 1 bit/sec rate. The format
|
|
is presented below.
|
|
|
|
+-------------+------+----------+-----+------+----------+-----+------+----
|
|
|| | | Repeat 1 | | | Repeat 2 | | |
|
|
|| | word | | | word | | | word |
|
|
|| Dotting | sync | of | Dot | sync | of | Dot | sync |
|
|
|| | | | | | | | |
|
|
|| | | Word 1 | | | Word 1 | | |
|
|
+-------------+------+----------+-----+------+----------+-----+------+----
|
|
101 11 48 37 11 48 37 11
|
|
|
|
---+----------+-----+------+----------+-----+------+----------+-----+----
|
|
| Repeat 3 | | | Repeat 4 | | | Repeat 5 | |
|
|
| | | word | | | word | | |
|
|
| of | Dot | sync | of | Dot | sync | of | Dot |
|
|
| | | | | | | | |
|
|
| Word 1 | | | Word 1 | | | Word 1 | |
|
|
---+----------+-----+------+----------+-----+------+----------+-----+----
|
|
48 37 11 48 37 11 48 37
|
|
|
|
---+------+----------+-------- -------+----------+
|
|
| | Repeat 1 | | Repeat 5 ||
|
|
| word | | | ||
|
|
| sync | of | ... | of ||
|
|
| | | | ||
|
|
| | Word 2 | | Word 2 ||
|
|
---+------+----------+-------- -------+----------+
|
|
|
|
A 37-bit dotting sequence and an 11-bit word sync sequence are sent
|
|
to permit land stations to achieve synchronization with the incoming
|
|
data, except at the first repeat of word 1, where a 101-bit dotting
|
|
sequence is used. Each word contains 48 bits, including parity, and
|
|
is repeated five times together with the 37-bit dotting and 11-bit
|
|
word sync sequences; it is then referred to as a word block. For a
|
|
multi-word message, the second word block is formed the same as the
|
|
first word block including the 37-bit dotting and 11-bit word sync
|
|
sequences. A word is formed by encoding the 36 content bits into a
|
|
(48, 36) BCH code that has a distance of 5, (48, 36; 5). The left-
|
|
most bit (earliest in time) shall be designated the most-significant
|
|
bit. The 36 most-significant bits of the 48-bit field shall be the
|
|
content bits. The generator polynomial for the code is the same as
|
|
for the (40, 28; 5) code used on the forward control channel.
|
|
|
|
Each RVC message can consist of one or two words. The types of
|
|
messages to be transmitted over the reverse voice channel are as
|
|
follows:
|
|
|
|
o Order Confirmation Message
|
|
o Called-Address Message
|
|
|
|
The message formats are as follows:
|
|
|
|
|
|
Order Confirmation Message:
|
|
|
|
+---+------+---+-------+------+-------+-----------+---------+
|
|
| F | NAWC | T | | | | RSVD | |
|
|
| | | | | | | | |
|
|
| = | = | = | LOCAL | ORDQ | ORDER | = | P |
|
|
| | | | | | | | |
|
|
| 1 | 00 | 1 | | | | 000 ... 0 | |
|
|
+---+------+---+-------+------+-------+-----------+---------+
|
|
1 2 1 5 3 5 19 12
|
|
|
|
|
|
Called-Address Message
|
|
|
|
Word 1 - First Word of the Called-Address
|
|
|
|
+---+------+---+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
| F | NAWC | T | | | | | | | | | |
|
|
| | | | 1st | 2nd | | | | | 7th | 8th | |
|
|
| = | = | = | Digit | Digit | ... | ... | ... | ... | Digit | Digit | P |
|
|
| | | | | | | | | | | | |
|
|
| 1 | 01 | 0 | | | | | | | | | |
|
|
+---+------+---+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
1 2 1 4 4 4 4 4 4 4 4 12
|
|
|
|
Word 2 - Second Word of the Called-Address
|
|
|
|
+---+------+---+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
| F | NAWC | T | | | | | | | | | |
|
|
| | | | 9th | 10th | | | | | 15th | 16th | |
|
|
| = | = | = | Digit | Digit | ... | ... | ... | ... | Digit | Digit | P |
|
|
| | | | | | | | | | | | |
|
|
| 0 | 00 | 0 | | | | | | | | | |
|
|
+---+------+---+-------+-------+-----+-----+-----+-----+-------+-------+---+
|
|
1 2 1 4 4 4 4 4 4 4 4 12
|
|
|
|
|
|
The fields are descriptions a the same as those for the Reverse Control
|
|
channel above.
|
|
|
|
|
|
|
|
Overhead Message
|
|
|
|
A three-bit OHD field is used to identify the overhead message
|
|
types. Overhead message type codes are listed in the table below.
|
|
They are grouped into the following functional classes:
|
|
|
|
o System parameter overhead message
|
|
o Global action overhead message
|
|
o Registration identification message
|
|
o Control-filler message
|
|
|
|
Overhead messages are send in a group called an overhead message
|
|
train. The first message of the train must be the system parameter
|
|
overhead message. The desired global action messages and/or a
|
|
registration ID message must be appended to the end of the system
|
|
parameter overhead message. The total number of words in an overhead
|
|
message train is one more than the value of the NAWC field contained
|
|
in the first word of the system parameter overhead message. The last
|
|
word in the train must be set to '0'. For NAWC-counting purposes,
|
|
inserted control-filler messages must not be counted as part of the
|
|
overhead message train.
|
|
|
|
The system parameter overhead message must be sent every .8 +/- .3
|
|
seconds on each of the following control channels:
|
|
|
|
o combined paging-access forward channel.
|
|
o Separate paging forward control channel
|
|
o Separated access forward control channel
|
|
when the control-filler message is sent with the WFOM bit
|
|
set to '1'.
|
|
|
|
The global action messages and the registration identificaion message
|
|
are sent on an as needed basis.
|
|
o The system parameter for overhead message consists of two
|
|
two words.
|
|
|
|
|
|
Word 1
|
|
|
|
+-------+-----+----------+------+------+-----+------------+
|
|
| T T | | | RSVD | | OHD | |
|
|
| 1 2 | | | | | | |
|
|
| = | DCC | SID1 | = | NAWC | = | P |
|
|
| | | | | | | |
|
|
| 11 | | | 000 | | 110 | |
|
|
+-------+-----+----------+------+------+-----+------------+
|
|
2 2 14 3 4 3 12
|
|
|
|
|
|
Word 2
|
|
|
|
+-------+-------+-----+-----+------+------+-----+------+---
|
|
| T T | | | | | | | RSVD |
|
|
| 1 2 | | | | | | | |
|
|
| = | DCC | S | E | REGH | REGR | DTX | = |
|
|
| | | | | | | | |
|
|
| 11 | | | | | | | 0 |
|
|
+-------+-------+-----+-----+------+------+-----+------+---
|
|
2 2 1 1 1 1 1 1
|
|
|
|
---+-------+-----+-----+----------+-----+-------+-----------+
|
|
| | | | | | OHD | |
|
|
| | | | | | | |
|
|
| N - 1 | RCF | CPA | CMAX - 1 | END | = | P |
|
|
| | | | | | | |
|
|
| | | | | | 111 | |
|
|
---+-------+-----+-----+----------+-----+-------+-----------+
|
|
5 1 1 7 1 3 12
|
|
|
|
|
|
Overhead Message Types
|
|
+----------------------------------------------------------+
|
|
| Code Order |
|
|
+----------------------------------------------------------+
|
|
| 000 Registration ID |
|
|
| 001 Control-filler |
|
|
| 010 reserved |
|
|
| 011 reserved |
|
|
| 100 global action |
|
|
| 101 reserved |
|
|
| 110 Word 1 of system parameter message |
|
|
| 111 Word 2 of system parameter message |
|
|
+----------------------------------------------------------+
|
|
|
|
The interpretation of the data fields:
|
|
|
|
T T - Type field. Set to '11' indicating an overhead word.
|
|
1 2
|
|
OHD - Overhead message type field. The OHD field of Word 1 is
|
|
set to '110' indicating the first word of the system
|
|
parameter overhead message. The OHD field of Word 2 is
|
|
set to '111' indicating the second word of the system
|
|
parameter overhead message.
|
|
DCC - Digital Color Code field.
|
|
SID1 - First part of the system identification field
|
|
NAWC - Number of Additional Words Comming field. In Word 1 this
|
|
field is set to one fewer than the total number of words
|
|
in the overhead message train.
|
|
S - Serial number field.
|
|
E - Extended address field.
|
|
REGH - Registration field for home stations.
|
|
REGR - Registration field for roaming staions.
|
|
DTX - Discountinuous transmission field.
|
|
N-1 - N is the number of paging channels in the system.
|
|
RCF - Read-control-filler field.
|
|
CPA - Combined paging/access field
|
|
CMAX-1 - CMAX is the number of access channels in the system.
|
|
END - End indication field. Set to '1' to indicate the last word
|
|
and '0' if not the last word.
|
|
RSVD - Reserved for future use, all bit must be set as indicated.
|
|
P - Parity field.
|
|
|
|
|
|
Each global action overhead message consists of one word. Any number
|
|
of global action messages can be appended to a system parameter over-
|
|
head message.
|
|
|
|
Here are the global action command formats:
|
|
|
|
|
|
Rescan Global Action Message
|
|
|
|
+-------+-------+------+---------------+-------+-------+-------------+
|
|
| T T | | ACT | RSVD = | | OHD | |
|
|
| 1 2 | | | | | | |
|
|
| = | DCC | = | | END | = | P |
|
|
| | | | 000 ... 0 | | | |
|
|
| 11 | | 0001 | | | 100 | |
|
|
+-------+-------+------+---------------+-------+-------+-------------+
|
|
2 2 4 16 1 3 12
|
|
|
|
Registration Increment Global Action Message
|
|
|
|
+-------+-----+------+---------+--------+-------+-------+------------+
|
|
| T T | | ACT | | | | OHD | |
|
|
| 1 2 | | | | RSVD = | | | |
|
|
| = | DCC | = | REGINCR | | END | = | P |
|
|
| | | | | 0000 | | | |
|
|
| 11 | | 0010 | | | | 100 | |
|
|
+-------+-----+------+---------+--------+-------+-------+------------+
|
|
2 2 4 12 4 1 3 12
|
|
|
|
New Access Channel Set Global Action Message
|
|
|
|
+-------+-------+-------+--------+----------+-------+-------+----------+
|
|
| T T | | ACT | | | | OHD | |
|
|
| 1 2 | | | | RSVD = | | | |
|
|
| = | DCC | = | NEWACC | | END | = | P |
|
|
| | | | | 00000 | | | |
|
|
| 11 | | 0110 | | | | 100 | |
|
|
+-------+-------+-------+--------+----------+-------+-------+----------+
|
|
2 2 4 11 5 1 3 12
|
|
|
|
|
|
Overload Control Global Action Message
|
|
|
|
+-------+-----+-------+---+---+---+-- --+---+---+---+-----+-----+------+
|
|
| T T | | ACT | O | O | O | | O | O | O | | OHD | |
|
|
| 1 2 | | | L | L | L | | L | L | L | | | |
|
|
| = | DCC | = | C | C | C | ... | C | C | C | END | = | P |
|
|
| | | | | | | | | | | | | |
|
|
| 11 | | 0110 | 0 | 1 | 2 | | 13| 14| 15| | 100 | |
|
|
+-------+-----+-------+---+---+---+-- --+---+---+---+-----+-----+------+
|
|
2 2 4 1 1 1 1 1 1 1 3 12
|
|
|
|
|
|
Access Type Parameters Global Action Message
|
|
|
|
+-------+-----+------+-------+-----------+-------+-------+-----------+
|
|
| T T | | ACT | | | | OHD | |
|
|
| 1 2 | | | | RSVD = | | | |
|
|
| = | DCC | = | BIS | | END | = | P |
|
|
| | | | | 0 ... 000 | | | |
|
|
| 11 | | 1001 | | | | 100 | |
|
|
+-------+-----+------+-------+-----------+-------+-------+-----------+
|
|
2 2 4 1 15 1 3 12
|
|
|
|
|
|
Access Attempt Parameters Global Action Message
|
|
|
|
+-------+-------+---------+-----------+-----------+-----------+---
|
|
| T T | | ACT | | | |
|
|
| 1 2 | | | MAXBUSY | MAXSZTR | MAXBUSY |
|
|
| = | DCC | = | | | |
|
|
| | | | - PGR | - PGR | - OTHER |
|
|
| 11 | | 1010 | | | |
|
|
+-------+-------+---------+-----------+-----------+-----------+---
|
|
2 2 4 4 4 4
|
|
|
|
------+-----------+-------+-------+-----------+
|
|
| | | OHD | |
|
|
| MAXSZTR | | | |
|
|
| | END | = | P |
|
|
| - OTHER | | | |
|
|
| | | 100 | |
|
|
------+-----------+-------+-------+-----------+
|
|
4 1 3 12
|
|
|
|
|
|
Local Control 1 Message
|
|
|
|
+-------+-------+-------+-----------------+-------+-------+----------+
|
|
| T T | | ACT | | | OHD | |
|
|
| 1 2 | | | | | | |
|
|
| = | DCC | = | LOCAL CONTROL | END | = | P |
|
|
| | | | | | | |
|
|
| 11 | | 1110 | | | 100 | |
|
|
+-------+-------+-------+-----------------+-------+-------+----------+
|
|
2 2 4 16 1 3 12
|
|
|
|
|
|
Local Control 2 Message
|
|
|
|
+-------+-------+-------+-----------------+-------+-------+----------+
|
|
| T T | | ACT | | | OHD | |
|
|
| 1 2 | | | | | | |
|
|
| = | DCC | = | LOCAL CONTROL | END | = | P |
|
|
| | | | | | | |
|
|
| 11 | | 1111 | | | 100 | |
|
|
+-------+-------+-------+-----------------+-------+-------+----------+
|
|
2 2 4 16 1 3 12
|
|
|
|
|
|
The interpretation of the data fields are as follows:
|
|
|
|
T T - Typ efield. Set to '11' indicating overhead word.
|
|
1 2
|
|
ACT - Global action field (see table below).
|
|
BIS - Busy-idle status field.
|
|
DCC - Digital Color Code.
|
|
OHD - Overhead Message type field. Set to '100' indicating the
|
|
global action message.
|
|
REGINCR - Registration increment field.
|
|
NEWACC - News access channel starting point field.
|
|
MAXBUSY - Maximum busy occurrences field (page response).
|
|
- PGR
|
|
MAXBUSY - Maximum busy occurences field (other accesses).
|
|
- OTHER
|
|
MAXSZTR - Maximum seizure tries field (page response).
|
|
- PRG
|
|
MAXSZTR - Maximum seizure tries field (other accesses).
|
|
- OTHER
|
|
OLCN - Overload class field (N = 0 to 15)
|
|
END - End indication field. Set to '1' to indicate the last word
|
|
of the overhead message train; set to '0' if not last word.
|
|
RSVD - Reserved for future use, all bits must be set as indicated.
|
|
LOCAL - May be set to any bit pattern.
|
|
CONTROL
|
|
P - Parity field.
|
|
|
|
|
|
The registration ID message consits of one word. When sent, the
|
|
message must be appended to a system parameter overhead message in
|
|
addition to any global action messages.
|
|
|
|
|
|
+-------+-------+-------------+-------+-------+-----------+
|
|
| T T | | | | OHD | |
|
|
| 1 2 | | | | | |
|
|
| = | DCC | REGID | END | = | P |
|
|
| | | | | | |
|
|
| 11 | | | | 000 | |
|
|
+-------+-------+-------------+-------+-------+-----------+
|
|
2 2 20 1 3 12
|
|
|
|
The interpretation of the data fields:
|
|
|
|
T T - Type field. Set to '11' indicating overhead word.
|
|
1 2
|
|
DCC - Digital color code field.
|
|
OHD - Overhead message type field. Set to '000' indicating the
|
|
registration ID message.
|
|
REGID - Registration ID field.
|
|
END - End indication field. Set to '1' to indicate last word of
|
|
the overhead message train; set to '0' if not.
|
|
P - Parity field.
|
|
|
|
|
|
The control-filler message consists of one word. It is sent whenever
|
|
there is no other message to be sent on the forward control channel.
|
|
It may be inserted between messages as well as between word blocks of
|
|
a mulitword message. The control-filler message is chosen so that
|
|
when it is sent, the 11-bit word sequence will not appear in the
|
|
message stream, independent of the busy-idle bit status.
|
|
|
|
The control-filler message is also used to specify a control mobile
|
|
attenuation code (CMAC) for use by mobile stations accessing the
|
|
system on the reverse control channel, and a wait-for-overhead-
|
|
message bit (WFOM) indicating whether or not mobile staions must
|
|
read an overhead message train before accessing the system.
|
|
|
|
|
|
+-------+-----+------+------+------+--+------+---+------+----+-----+-----+
|
|
| T T | | | | RVSD | | RVSD | | | | OHD | |
|
|
| 1 2 | | | | | | | | | | | |
|
|
| = | DCC |010111| CMAC | = |11| = | 1 | WFOM |1111| = | P |
|
|
| | | | | | | | | | | | |
|
|
| 11 | | | | 00 | | 00 | | | | 001 | |
|
|
+-------+-----+------+------+------+--+------+---+------+----+-----+-----+
|
|
2 2 6 3 2 2 2 1 1 4 3 16
|
|
|
|
Interpretation of the data fields:
|
|
|
|
T T - Type field. Set to '11' indicating overhead word.
|
|
1 2
|
|
DCC - Digital color code field.
|
|
CMAC - Control mobile attenuation field. Indicates the mobile
|
|
station power level associated with the reverse control
|
|
channel.
|
|
RVSD - Reserved for future use; all bits must be set as indicated.
|
|
WFOM - Wait-for-overhead-message field.
|
|
OHD - Overhead message type field. Set to '001' indicating the
|
|
control-filler word.
|
|
P - Parity field.
|
|
|
|
|
|
Data Restrictions
|
|
|
|
The 11-bit sequence (11100010010) is shorter than the length of a
|
|
word, and therefore can be embedded in a word. Normally, embedded
|
|
word-sync will not cause a problem because the next word sent will not
|
|
have the word-sync sequence embedded in it. There are, however, three
|
|
cases in which the word-sync sequence may appear periodically in the
|
|
FOCC stream. They are as follows:
|
|
|
|
o the overhead message
|
|
o the control-filler message
|
|
o Mobile station control messages with pages to mobile stations
|
|
with certain central office codes.
|
|
|
|
These three cases are handled by:
|
|
|
|
1. Restricting the overhead message transmission rate to about
|
|
once per second
|
|
2. designing the control-filler message to exclude the word-
|
|
sync sequence, taking into account the various busy-idle
|
|
bits
|
|
3. Restricting the use of certian office codes
|
|
|
|
|
|
If the mobile station control message is examined with the MIN1
|
|
separated into NXX-X-XXX as described earlier (where NXX is the
|
|
central office code, N represents a number from 2 - 9, and X
|
|
represents a number from 0-9) the order and order qualifications
|
|
table can be used to deduce when the word-sync word would be sent.
|
|
If a number of mobile stations are paged consecutively with the same
|
|
central office code, mobile stations that are attempting to synchronize
|
|
to the data stream may not be able to doso because of the presence of
|
|
the false word sync sequence. Therefore, the combinations of central
|
|
office codes and groups of line numbers appearing in the following
|
|
table must not be used for mobile stations.
|
|
|
|
|
|
RESTRICTED CENTRAL OFFICE CODES
|
|
+-------------------------------------------------------------------------+
|
|
| Central |
|
|
| T T DCC NXX X XXX Office Thousands |
|
|
| 1 2 Code Digit |
|
|
+-------------------------------------------------------------------------+
|
|
| 01 11 000100(1)0000 ... ... 175 0 to 9 |
|
|
| 01 11 000100(1)0001 ... ... 176 0 to 9 |
|
|
| 01 11 000100(1)0010 ... ... 177 0 to 9 |
|
|
| 01 11 000100(1)0011 ... ... 178 0 to 9 |
|
|
| 01 11 000100(1)0100 ... ... 179 0 to 9 |
|
|
| 01 11 000100(1)0101 ... ... 170 0 to 9 |
|
|
| 01 11 000100(1)0110 ... ... 181 0 to 9 |
|
|
| 01 11 000100(1)0111 ... ... 182 0 to 9 |
|
|
| 0Z 11 100010(0)1000 ... ... 663 0 to 9 |
|
|
| 0Z 11 100010(0)1001 ... ... 664 0 to 9 |
|
|
| 0Z 11 100010(0)1010 ... ... 665 0 to 9 |
|
|
| 0Z 11 100010(0)1011 ... ... 666 0 to 9 |
|
|
| 0Z Z1 110001(0)0100 ... ... 899 0 to 9 |
|
|
| 0Z Z1 110001(0)0101 ... ... 800 0 to 9 |
|
|
| 0Z ZZ 111000(1)0010 ... ... 909 0 to 9 |
|
|
| 00 ZZ 011100(0)1001 0ZZZ ... 568 1 to 7 |
|
|
| 00 ZZ 111100(0)1001 0ZZZ ... 070 1 to 7 |
|
|
| 00 ZZ 001110(0)0100 10ZZ ... 339 8,9,0 |
|
|
| 00 ZZ 011110(0)0100 10ZZ ... 595 8,9,0 |
|
|
| 00 ZZ 101110(0)0100 10ZZ ... 851 8,9,0 |
|
|
| 00 ZZ 111110(0)0100 10ZZ ... 007 8,9,0 |
|
|
| 0Z ZZ 000011(1)0100 0010 ... 150 2 |
|
|
| 0Z ZZ 000111(1)0001 0010 ... 224 2 |
|
|
| 0Z ZZ 001011(1)0001 0010 ... 288 2 |
|
|
| 0Z ZZ 001111(1)0001 0010 ... 352 2 |
|
|
| 0Z ZZ 010011(1)0001 0010 ... 416 2 |
|
|
| 0Z ZZ 010111(1)0001 0010 ... 470 2 |
|
|
| 0Z ZZ 011011(1)0001 0010 ... 544 2 |
|
|
| 0Z ZZ 011111(1)0001 0010 ... 508 2 |
|
|
| 0Z ZZ 100011(1)0001 0010 ... 672 2 |
|
|
| 0Z ZZ 100111(1)0001 0010 ... 736 2 |
|
|
| 0Z ZZ 101011(1)0001 0010 ... 790 2 |
|
|
| 0Z ZZ 101111(1)0001 0010 ... 864 2 |
|
|
| 0Z ZZ 110011(1)0001 0010 ... 928 2 |
|
|
| 0Z ZZ 110111(1)0001 0010 ... 992 2 |
|
|
| 0Z ZZ 111011(1)0001 0010 ... 056 2 |
|
|
| 0Z ZZ 111111(1)0001 0010 ... ... 2 |
|
|
+-------------------------------------------------------------------------+
|
|
|
|
|
|
1. In each case, Z represents a bit that may be 1 or 0.
|
|
2. Some codes are not used as central office codes in the US at this
|
|
time. They are included for completeness.
|
|
3. The bit in parentheses is the busy-idle bit.
|
|
|
|
|
|
Well there is your signaling in a nutshell. Please note I hardly have
|
|
the most up-to-date signalling data. Basically what was presented
|
|
here was a skeleton, the bare bones without all the additions. There
|
|
are some additions that are system specific. As I get updates I'll be
|
|
sure to share them with the rest of you. I would be interested in
|
|
any feedback, so, if you have something to say, send it to:
|
|
|
|
oblivion@atdt.org
|
|
|
|
In the last article I said that there would be a listing of SID codes
|
|
accompanying the article. Well, I forgot to edit that line out, but
|
|
if you would like a copy of it, just mail me at the above address an
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you shall receive one.
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In the next article I will be going indepth on the actual hardware
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behind the Mobile telephone, the chip sets, and its operation.
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I will also publish any updates to the previous material I find, as
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well as information on the transitory NAMPS system that will be used
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to bridge the existing AMPS cellular network over to the ISDN
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compatible fully digital network.
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Yet another...
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-=Restricted -=Data -=Transmission
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Truth is cheap... but information costs!
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