With callback verification, the answering modem that successfully
completes password verification with a calling modem hangs up, then
calls the modem back. The modems then pass data.
With callback dial restriction, the answering modem calls back only
stored Phonebook numbers, not numbers sent by a calling modem.
Enable these functions as follows.
Enabling Callback Verification and Dial Restriction
Configure password verification, as described above.
Use the AT
callback phone number source:
• The local modem (AT
• The remote modem (AT
Store a callback telephone number in the device selected in the
previous step, using the AT&Z (Enter Phone Number) command.
If you selected the remote modem as the callback-number source,
use the AT
is mandatory (AT
With the Mandatory option, the remote modem must supply a
callback number during its initial call, or the local modem
disconnects and does not make a callback.
With the Optional option, the remote modem may establish a call
without supplying a callback number. The local modem does not
To prevent the local modem from executing an Auto Redial
command, issue the AT
To prevent the modem from calling any number except those stored
in the Phonebook, issue the AT
ZC parameter default value is Off (AT
ZC command* in the local modem to specify the
ZCn, where n specifies a Phonebook entry)
ZC10). This option does not use the
ZR command to specify whether supplying the number
ZR1) or optional (AT