V.25Bis Command Set - ZyXEL Communications Omni TA128 User Manual

There are two modes of synchronous operation:
1. Asynchronous commands, synchronous data (AT&M1): The
TA128 accepts AT commands in asynchronous mode. Once the
call is connected, it enters synchronous mode for data
transmission.
2. Synchronous mode (AT&M3*I1): The TA128 accepts
synchronous commands from V.25 bis or a PC with an add-on
synchronous card, and exchanges data synchronously with a
remote TA.
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Note: The TA128 does not support network independent clock
compensation. The synchronous timing source must be
supplied by the TA128 , which is phase locked to the network
synchronous clock.
When in V.25bis command mode, the TA128 supports the bit-
oriented HDLC (High-Level Link Control) synchronous protocol
which most synchronous communication links use. Use AT*Ii to
enable V.25bis commands. For synchronous applications the TA is
set for use with one application, in normal situations. Save the
desired settings in the power-on profile and the TA will start up in
synchronous mode with V.25bis enabled. A special command set
RST is provided to get the TA back to asynchronous AT command
mode from V.25bis mode.
When the TA is used as a DCE device with a router or main-frame
system, use the following command string for best results:
AT&S1&M3*I1&W0Z0

V.25bis Command Set

Command Messages
CRN <dial string
CRSn
PRNn;<number>
Dial command with number provided.
Dial command with number from memory,
0<=n<=39; n is the memory location.
Saves <number> to address n (0<=n<=39).
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