US Robotics COURIER - CHAPTER 6. ASYNCHRONOUS DIALING AND ANSWERING; Modulation and Signaling Standards

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COURIER HIGH SPEED MODEMS
CHAPTER 6. ASYNCHRONOUS DIALING AND ANSWERING
The information in this chapter applies to asynchronous calls
only.
For synchronous operations, refer to Chapter 7.
BEFORE CONNECTING
For two modems to connect and exchange data, they must use
the same modulation standard and, for error control to be
successful, the same error control protocol. The end-to-end
devices (the computers, or DTEs) must use the same word
length, parity, and number of stop bit settings.
Modulation/Standards
The Courier modem adheres to the following modulation and
signaling standards.
USR-HST
CCITT V.32
bis
CCITTV.32
V.22
bis
Bell 212A/
CCITTV.22
CCITTV.23
CCITTV.25
Bell 103
or
CCITTV.21
CCITT V.42
CCITT V.42
bis
MNP
CCITTV.54
16.8K,
14.4K/12K/9600/7200/ 4800 bps (Dual
Standard and HST modems)
14.4K/12K/9600/7200/4800 bps (Dual
Standard and V.32 bis modems)
9600 I 4800 bps (Dual Standard and V .32 bis
modems)
2400 bps
1200 bps
1200 bps with 75 bps back channel (British
phone system)
Answer sequence for calls originating outside
the U.S. and Canada
300 bps
LAPM error control, 1200 bps and higher
Data compression, 1200 bps and higher
Levels 2, 3 and 4 error control, level 5 data
compression, 1200 bps and higher
Analog digital and remote digital loopback
testing
Asynchronous Operations 6-1