64 lines
3.8 KiB
Plaintext
64 lines
3.8 KiB
Plaintext
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APPENDIX A : Standards
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V.21 Standard for modem communications at 300 bps. Modems made in
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the US or Canada follow the Bell 103 standard. However, the
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modem can be set to answer V.21 calls from overseas.
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V.22 Standard for modem communications at 1200 bps, compatible
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with the Bell 212A standard observed in the US and Canada.
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V.22 bis Standard for modem communications at 2400 bps. The standard
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includes an automatic link negotiation fallback to 1200 bps
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and compatibility with Bell 212A/V.22 modems.
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V.23 Standard for modem communications at 1200 bps with a 75 bps
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back channel.
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V.24 Standards layed down by the CCITT for interfacing a digital
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device to a PTT-supplied modem. V.24 is also used as an
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interface standard for connecting a peripheral device, such
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as a visual display unit or a printer, to a computer.
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V.25 Standard for modem communications that specifies an answer
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tone different from the Bell answer tone used in the US and
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Cananda.
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V.32 Standard for modem communications at 9600 bps and 4800 bps.
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V.32 modems fall back at 4800 bps when line quality is
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impaired, and fall forward again to 9600 bps when line
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quality improves.
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V.32 bis Standard that extends the V.32 connection range: 4800,7200,
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9600, 12K and 14.4K bps. V.32 bis modems fall back to the
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next lower speed when line quality is impaired, and fall back
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further as necessary. They fall forward to the next higher
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speed when line quality improves.
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V.34 28.800 CCITT standard
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V.34+ 31.200 & 33.600, currently only supported by US Robotics
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(V.EveryThing modems) under consideration by CCITT.
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V.35 See V.24.
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V.42 Standard for modem communications that defines a two-stage
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process of detection and negotiation for LAPM error control.
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V.42 also supports the MNP error control protocol.
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V.42 bis An extention of V.42 that defines a specific data compression
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scheme for use with V.42 and MNP error control.
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X.3 It describes the functions of an X.25 PAD and the parameters
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used to control its operation.
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X.21 Interface between DTE and DCE for synchronous operation on
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on public data networks.
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X.25 Interface between DTE and DCE for terminals operating in
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packet mode on public data networks.
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X.28 It defines the interactions between a terminal and an X.25
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PAD.
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X.29 It defines the interactions between a host and its associated
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PAD.
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X.75 ISDN, EuroStandard, 64000.
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X.400 Message handling systems : System model and service elements.
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X.401 Message handling systems : Basic service elements and
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optional user facilities.
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X.408 Message handling systems : Encoded information type
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convertion rules.
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X.409 Message handling systems : Presentation transfer syntax and
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notation.
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X.410 Message handling systems : Remote operations and reliable
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transfer server.
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X.411 Message handling systems : Message transfer layer.
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X.420 Message handling systems : Interpersonal messaging user agent
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layer.
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X.430 Message handling systems : Access protocol for teletex
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terminals.
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X.500 The directory (OSI Directory Services).
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