Table of Contents
Advertisement
3.7
ITU-T V.25 bis commands
V. 25 bis mode provide with an alternate set of commands and
responses to AT commands. The V.25 bis mode performs dialling
functions in the asynchronous or synchronous mode according to the
ITU-T.
The V.25 bis defines modem behaviour only while the modem is
disconnected from the line, or while the modem is off-hook and is
attempting to establish a connection. The modem is no longer in
V.25 bis mode after the connection has been established.
In V.25 bis Synchronous mode, only the synchronous Data Link
Control (SDLC), which is more common in use, is supported by the
modem.
During automatic calling and answering procedure CD (109) follows
the condition of CTS (106).
The selection of commands is restricted to those described in V.25
bis, except for the SAT command which is used to return to AT
command mode. V.25 bis commands do not include any modem
configuration commands . The modem must therefore be configured
by means of AT commands or via display before entering V.25 bis
mode. All relevant parameters set by AT commands are also valid for
operating in the V.25 bis.
All commands are terminated with "Line Feed" (0AHex) and not
"Carriage Return" (ODHex) as in AT command mode. (CR, LF is a
legal terminating sequence).
To insure that the modem will start in V.25 bis mode after a power
down you should give the following command sequence.
AT+V&WSY gts]
Sets ITU-T V.25 bis command
mode.
LZTR104006 Rt.00
3-63
ZAT
14.4/14.4-7 and Zat 19.2/19.2-7
Advertisement
Table of Contents
