Help with fax reception

Hey all.

I have FreePBX 2.9.0 installed with Asterisk 1.8.5, DAHDI running a PRI connected to the system. Everything seems to work except receiving a fax. I have the fax configuration module installed, res_fax is installed, each extension is setup for receiving faxes with a wait for fax at the start of the call.

My “fax show capabilities” command shows:

Registered FAX Technology Modules:

Type : Spandsp
Description : Spandsp FAX Driver
Capabilities : SEND RECEIVE T.38 G.711

1 registered modules

The call comes in, hits the WAIT, but then just goes on and rings the extension as if it were a voice call and did not detect the fax tones. Dialing directly into extension 666 does give me the fax carrier signal. Did I miss something rather basic here?