Configuring Voice Services
Using a FAX Machine
Cisco Small Business ATA Administration Guide
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4
•
Echo Canceller
: no
•
Silence suppression
: no
•
Preferred Codec
: G.711
•
Use pref. codec only
: yes
STEP 4
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
STEP 5
Enable T.38 fax on the SPA 2102 by configuring the following parameter on the
Line tab for the FXS port to which the FAX machine is connected:
FAX_Passthru_Method: ReINVITE
NOTE
If a T.38 call cannot be set-up, then the call should automatically revert to
G.711 fallback.
STEP 6
If you are using a Cisco media gateway use the following settings:
Make sure the Cisco gateway is correctly configured for T.38 with the SPA dial
peer. For example:
fax protocol T38
fax rate voice
fax-relay ecm disable
fax nsf 000000
no vad
Fax Troubleshooting
If 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.
