Fax Troubleshooting - Linksys RTP300 - Broadband Router With 2 Phone Ports Administration Manual

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
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.
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:
1. Verify that your fax machine is set to a speed between 7200 and 14400.
2. Send a test fax in a controlled environment between two Linksys ATAs.
3. Determine the success rate.
4. Monitor the network and record the following statistics:
• Jitter
• Loss
• Delay
5. If faxes fail consistently, capture a copy of the web interface settings by selecting Save As >
Web page, complete from the administration web server page. You can send this
configuration file to Technical Support.
6. Enable and capture the debug log. For instructions, refer to
NOTE: You may also capture data using a sniffer trace.
7. Identify the type of fax machine connected to the Linksys ATA device.
Linksys ATA Administration Guide
Configuring Voice Services
Using a FAX Machine (SPA2102, SPA3102 or SPA8000)
Appendix D, "Troubleshooting."
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