Advanced Options for Voice Services
Optimizing Fax Completion Rates
Administration Guide
137
9
•
Preferred Codec
: G.711u (USA) or G.711a (rest of the world)
•
Use pref. codec only
: yes
•
Silence Supp Enable
: no
•
Echo Canc Enable
: no
•
FAX Passthru Method:
ReINVITE
STEP 6
Click
Submit
to save your settings or click
Cancel
to abandon the unsaved
settings.
STEP 7
If you are using a Cisco media gateway for PSTN termination, disable T.38 (fax
relay) and enable fax using modem passthrough. For example:
modem passthrough nse payload-type 110 codec g711ulaw
fax rate disable
fax protocol pass-through g711ulaw
Note:
If a T.38 call cannot be set-up, then the call automatically reverts to G.711
fallback.
STEP 8
If you are using a Cisco media gateway, make sure the Cisco gateway is correctly
configured for T.38 with the dial peer. For example:
fax protocol T38
fax rate voice
fax-relay ecm disable
fax nsf 000000
no vad
Fax Troubleshooting
If you have problems sending or receiving faxes, complete the following steps:
STEP 1
Verify that your fax machine is set to a speed between 7200 and 14400.
STEP 2
Send a test fax in a controlled environment between two ATAs.
STEP 3
Determine the success rate.
STEP 4
Monitor the network and record the statistics for jitter, loss, and delay.
