I am using Cisco SPA2102’s for T38 faxing into a corporation with 20 fax machines.

I have a freeswitch box that acts as a router to route SIP from our carrier network into our customers private network. This is the only function this box performs.

The profiles on this box have:

<param name="inbound-late-negotiation" value="true"/>

<param name="t38-passthru" value="true"/>

Faxes complete 99% of the time.

If I enable <action application="set" data="proxy_media=true"/> right before the bridge it completely breaks T38 faxing. Success rate of 0%. Does anyone know why this is?

Thanks,

Colin