Draytek VigorIPPBX 3510 User Manual page 225

Hotline
Call Waiting
FAX Mode
Check the box to enable it. Type in the SIP URL in the field
for dialing automatically when you pick up the phone set.
Check this box to invoke this function. A notice sound will
appear to tell the user new phone call is waiting for your
response. Click hook flash to pick up the waiting phone call.
The FAX function mode. There are several options:
Transparent: FAX will be transmitted via voice channel; no
fax relay and no Codec change will be involved.
T.38 Relay: Using T.38 Fax Relay. This is the default value.
Bypass: Once FAX is detected, the Codec will automatically
switch to a high bit rate type (G.711a/u or G.726) to make
sure FAX can transmit successfully.
If this option is selected, the Vigor router will apply these two
following settings (FAX Bypass Codec and FAX Bypass
Codec Rate).
217
VigorIPPBX 3510 Series User's Guide