Case Communications syncro 1496, Reference Manual

Page: 83 / 192

6.4 Dial Backup
The relevant commands are:
''B Initiate dial backup
''D
Revert to leased line on DTR
''L Manual revert to leased line
*L Dial backup facility
Dial backup is the facility that enables your modem to initiate or receive a
call on its PSTN line if there is a failure on the leased line circuit.
Your modem can store up to twenty telephone numbers for autodialling
over the PSTN. Stored directory location 8 is used for the single line dial
backup number.
In the case of leased line failure, dial backup is initiated either
automatically or manually depending on the setting of the
*L
command.
To initiate dial backup manually you need only press the
DB
button, and
the modem will autodial the backup number stored. Manual dial backup
can also be initiated by software command
''B
. However, the modem will
only initiate dial backup if a telephone number is stored in N8.
If there is no number stored in position N8, the modem will act as a slave
modem and wait to be dialled from the master modem at the other end of
the failed leased line.
When your modem goes from leased line to dial backup mode, the PSTN
settings to which it will need to operate (data rate etc) are normally
determined by one of the stored user configurations.
Master and Slave
The dial backup procedures described in this section refer to ''master'' and
''slave'' modems. The master modem is the modem which initiates the dial
backup calls. It is assigned by storing a telephone number in location N8
by the command:
ATN8&Z <telephone number><CR>
A slave modem expects the dial backup to be initiated by receiving a call on
the PSTN from a master modem. To assign your modem to act as a slave,
directory location N8 must not contain a telephone number – enter the
command:
ATN8&Z<CR>
X450-310851 Issue 2 6-7 Rev.0