158 lines
7.4 KiB
Plaintext
158 lines
7.4 KiB
Plaintext
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Disclaimer Notice:
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This file is presented as an INFORMATIONAL file only.
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Do not try any of the things mentioned in the text file
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as some of them are illegal to do. The bbs operator take
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NO responsibilty.
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---------------------------------------
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How Ma Bell Works
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In this article, I will first describe the termination,
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wiring, and terminal hardware most commonly used in the Bell
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system, and I will include section on methods of using them.
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-------------
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LOCAL NETWORK
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-------------
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The local telephone network between the central
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office/exchange and the telephone subscribers can be briefly
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described as follows:
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From the central office (or local exchange) of a certain
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prefix(es), underground area trunks go to each area that has that
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prefix (Usually more than one prefix per area.) At every few
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streets or tract areas, the underground cables surface. They then
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go to the telephone pole (or back underground, depending on the
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area) and then to the subsribers house (or in the case of an
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apartment building or mutliline business, to a splitter or dis-
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tribution box/panel).
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Now that we have the basics, I'll try and go in-depth on the
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subject.
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UNDERGROUND CABLES
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------------------
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These are sometimes inter-office trunks, but usually in a
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residential area they are trunk lines that go to bridging heads
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or distribution cases. The cables are about 2-3 inches thick
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(varies), and are either in a metal or pvc-type pipe (or
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similiar). Rarely (maybe not in some remote rural areas) are the
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cables just 'alone' in the ground. Instead they are usually in
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an underground cement tunnel (resembles a small sewer or storm-
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drain.) The manholes are >heavy< and will say 'Bell system' on
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them. they can be opened with a 1/2 inch wide crowbar (Hookside)
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inserted in the top rectangular hole. There are ladder rungs to
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help you climb down. You will see the cable pipes on the wall,
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with the blue and white striped one being the inter-office trunk
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(at least in my area). The others are local lines, and are
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usually marked or color coded. There is almost always a posted
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color code chart on the wall, not to mention Telco manuals de-
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scribing the cables and terminals, so I need not get into detail.
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Also, there is usually some kind of test equipment, and often
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Bell test sets are left in there.
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BRIDGING HEADS
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The innocent-looking grayish-green boxes. These can be
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either trunk bridges or bridging for residences. The major trunk
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bridging heads are usually larger, and they have the 'Western
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Electric' logo at the bottom, whereas the normal bridging heads
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(which may be different in some areas-depending on the company
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you are served by. GTE B.H.'s look slightly different. Also, do
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not be fooled by sprinkler boxes!) They can be found in just
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about every city.
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To open a bridging head: if it is locked (and you're feeling
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destructive), put a hammer or crowbar (the same one you used on
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the manhole) in the slot above the top hinge of the right door.
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Pull hard, and the door will rip off. Very effective! If it isn't
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locked (as usual), take a 7/8 inch hex socket and with it, turn
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the bolt about 1/8 of a turn to the right (you should hear a
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spring release inside). Holding the bolt, turn the handle all the
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way to the left and pull out.
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To Check for a test-set (which are often left by Bell employees),
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go inside - First check for a test-set (which are often left
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by Bell employees). There should be a panel of terminals and
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wires. Push the panel back about an inch or so, and rotate the
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top latch (round with a flat section) downward. Release the
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panel and it will fall all the way forward. There is usually a
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large amount of wire and extra terminals. The test-sets are
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often hidden here, so don$ overlook it (Manuals, as well, are
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sometimes placed in the head). On the right door is a metal box
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of alligator clips. Take a few (Compliments of Bell.). On each
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door is a useful little round metal device. (Says 'insert gently'
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or' clamp gently - do not overtighten' etc..) On the front of
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the disc, you should find two terminals. These are for your test
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set. (If you dont have one, dont despair -I'll show you ways to
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make basic test sets later in this article).
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Hook the ring (-) wire to the 'r' terminal; and the tip (+)
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wire to the other. (By the way, an easy way to determine the
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correct polarity is with a 1.5v LED. Tap it to the term. pair,
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if it doesnt light, switch the poles until it does. When it
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lights,find the longer of the two LED poles: This one will be on
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the tip wire (+). Behind the disc is a coiled up cord. This
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should have two alligator clips on it.. Its very useful, because
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you dont have to keep connecting and disconnecting the fone (test
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set) itself, and the clips work nicely.
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On the terminal board, there should be about 10 screw
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terminals per side. Follow the wires, and you can see which
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cable pairs are active. Hook the clips to the terminal pair, and
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you're set! Dial out if you want, or just listen (If someone's
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on theline). Later, I'll show you a way to set up a true 'tap'
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that will let the person dial out on his line and receive calls
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as normal, and you can listen in the whole time. More about this
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later...
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On major prefix-area bridging heads, you can see 'local
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loops' ,which are two cable pairs (cable pair = ring+tip, a fone
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line) that are directly connected to each other on the terminal
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board. These 'cheap loops' as they are called, do not work
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nearLy as well as the existing ones set up in the switching
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hardware at the exchange office. (Try scanning your prefixes'
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00xx to 99xx #'s.) The tone sides will announce themselves with
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the 1008 hz loop tone, and the hang side will give no response.
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The first person should dial the 'hang' side, and the other
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person dial the tone side, and the tone should stop if you have
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got the right loop.)
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If you want to find the number of the line that you're on,
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you can either try to decipher the 'bridging log' (or whatever),
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which is on the left door. If that doesnt work, you can use the
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follwing:
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ANI # (Automatic Number ID)
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This is a Telco test number that reports to you the number
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that youre calling from (It's the same, choppy 'Bell bitch' voice
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that you get when you reach a disconnected #)
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For the 213 NPA - Dial 1223
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408 NPA - Dial 760
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914 NPA - Dial 990
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These are extremely useful when messing with any kind of
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line terminals, house boxes, etc.
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Now that we have bridging heads wired, we can go on... (dont
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forget to close and latch the box after all... Wouldnt want to GE
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and Telco people mad, now,would we?)
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Continued in: Ma Bell part II
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