fxo to fxs fax problem

jsheppard · ‎11-12-2008

I'm setting up a UC520. I have one analog line from POTS that is dedicated to fax. I have terminated that line on FXO interface 0/1/3. I have ran an analog telephone line from my fax machine and terminated on FXS port 0/0/0. I can make out fax ok, but when I try to fax in, the fax machnie rings, then answers, but no fax transmission. If I take UC500 out of picture and terminate pots line on fax machine directly, it receives fax ok. Am I missins a config somewhere?

Thanks,

smahbub · ‎11-18-2008

A common cause of fax relay problems is that the correctly configured dial peer is not the one that is matched. It is also common that there is no particular inbound VoIP dial-peer configured on the termination gateway, and Cisco IOS Software selects the first appropriate (and default) VoIP dial peer as the inbound dial peer. The parameters for this inbound dial peer may not match those of the outbound dial peer on the origination gateway.When you have a fax relay problem, though, make sure you have a dedicated inbound VoIP dial-peer on the termination router and that its configuration matches the configuration of the outbound VoIP dial-peer on the origination router.

jsheppard · ‎11-18-2008

I have figured this out. It was actually related to a config on the FXO ports. I removed the battery-reversal on the FXO port (no battery-reversal) and the fax transmission started working. Thanks for your help though.