Draytek Vigor2920n User Manual page 253

Loop through
Backup Phone Number
D i g i t M a p
D i g i t M a p
For the convenience of user, this page allows users to edit prefix number for the SIP account
with adding number, stripping number or replacing number. It is used to help user having a
quick and easy way to dial out through VoIP interface.
Enable
Prefix Number
Mode
Choose PSTN to enable loop through function.
When the VoIP phone is obstructs or the Internet breaks down
for some reasons, the backup phone will be dialed out to replace
the VoIP phone number. At this time, the phone call will be
changed from VoIP phone into PSTN call according to the loop
through direction chosen. Note that, during the phone switch,
the blare of phone will appear for a short time. And when the
VoIP phone is switched into the PSTN phone, the telecom co.
might charge you for the connection fee. Please type in backup
phone number (PSTN number/ISDN number) for this VoIP
phone setting.
Check this box to invoke this setting.
The phone number set here is used to add, strip, or replace the
OP number.
None - No action.
Add - When you choose this mode, the OP number will be
added with the prefix number for calling out through the
specific VoIP interface.
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Vigor2920 Series User's Guide