Limiting a fax rate on a POTS dial peer

[aaron.banks11]

Is there  a way to limit the outgoing fax rate on a pots dial peer?

[Chris Deren]

Why would you want to do that? POTS is POTS, there are no packets nor fax protocol to worry about. 

[aaron.banks11]

Well it seems that faxing is failing since converting from Nortel to Cisco.  So, the person onsite changed the fax to step down but he has told me that the fax is still sending at a higher rate.  I don't know how this could be but I am taking him at his word....hence my reason for the question.

[Chris Deren]

What is the connection between Cisco and Nortel. Can you provide description of the full call flow and identify each leg as IP, POTS/PRI, etc.

[Abhay Singh Reyal]

The fax rate voice setting restricts the fax rate to the codec bandwidth. This restriction means that, if the dial-peer is configured to use the default G.729 voice codec that compresses voice to 8 kbps, the fax rate voice setting would not allow fax calls to exceed this codec bandwidth. The fax would be limited to a bandwidth of 7200 BPS, even if it tried to initially negotiate at a higher bandwidth of 14400 BPS or 9600 BPS.

Check you configuration and call flow, if the FAX rate is getting modified due to above reason, you can hard-code the FAX rate on the voip dial-peer. 

If you are using a SIP, collect the ccsip messages and voice ccapi inout debug. Check the fax rate which is getting negotiated and hard-code it on the dial-peer accordingly. 

HTH 

Regards

Abhay