Verilink Productivity 500 (34-00236) Product Manual - Manual (Page 69)

V.25 bis Dialer Operation 500 TA Page 69
Chapter 11 V.25 bis Dialer Operation
GENERAL
V.25 bis is an autodialer option used by synchronous DTE to perform dialing
and terminal adapter control functions. The 500 TA supports a subset of the
CCITT V.25 bis recommendation, primarily intended for the dialing and
answering commands for HDLC or BISYNC modes of V.25 bis operation.
SELECTING V.25 bis
The V.25 bis option is selected using the AT@P1 command. To select V.25 bis,
type one of the following AT commands:
AT@P1 = VB for V.25 bis BISYNC mode or
AT@P1 = VH for V.25 bis HDLC mode.
The DTR pin is used to activate the V.25 bis dialer. When the DTR pin is
turned on, the dialer command setting is used to start the appropriate V.25 bis
mode. When you select V.25 bis dialer operation, the DTE SPEED is used to
configure the dialer port speed.
NOTE: The V.25 bis dialer option is not activated until the DTR signal has
been turned off and then back on. This will most likely occur when the asyn-
chronous DTE used to enter AT commands is disconnected from the DTE port
and the device which uses the V.25 bis dialing feature is connected. Once the
V.25 bis dialer is activated AT commands can no longer be entered.
OPERATION IN V.25 bis MODE
When the V.25 bis option is enabled, most 500 TA options still apply. Selecting
V.25 bis forces the 500 TA into the synchronous communications mode
(regardless of the synchronous mode option). Only the DCD pin option setting
applies when V.25 bis is enabled and the 500 TA is offline.
REACTIVATING THE AT COMMAND PROCESSOR
The V.25 bis dialer option and the AT command processor cannot be active at
the same time. Subsequently, once the V.25 bis dialer has been activated the
500 TA will have to be forced back to its factory default configuration in order
to reactivate the AT command processor. This is accomplished by placing the
switch labeled 1 on the 8-position switch located on the rear of the 500 TA into
the ON position and removing and reapplying power to the unit. AT commands
can now be entered and the V.25 bis dialer will no longer be active.