Ericsson ZAT 19.2 Operation Manual page 102

ommand sets.
In the V.25 bis mode, disconnecting the modem from the line is
always done by turning DTR OFF.
"To use the CCITT V25 bis commands, it is a
precondition that the DTR-signal can be controlled.
To control the parameter "DTR Delay" see register S25.
Synchronous V.25 bis command mode:
Synchronous operation in V.25 bis command mode can be selected
in any one of the following ways:
= Give AT&Mn+V in Hayes command mode (n=1, 2 or 3).
=> Enter CHANGE GENERAL CONF. menu via display, select
SYNC data format and V.25 bis command mode.
In order to utilise V.25 bis bit synchronous mode, a DTE that also
supports this command mode is necessary. The commands from
DTE and messages from the modem are sent in HDLC format.
iF [A IC [Message | |F {
F 7EH
A FFH
Cc 13H
Message _ Information field of the frame
FCS Frame check sequence.
Clocking:
The modem provides clocking via pin 15 and 17 at DTE interface for
communication with the local DTE. It is also possible to select DTE
provided timing (circuit 113).