Digium FXS and SpanDsp interface problem


This problem is not an Asterisk problem but since the DIgium cards are generally only used with Asterisk I am hoping someone can help.

I have a TDM10B FXS board installed. The zaptel and wctdm drivers are both loaded and the OS recognizes the card. I can open /dev/zaptel/1 and I can talk to it. I am able to ring a local phone and generate dialtone.

The problem I am having is getting dtmf digits from the attached handset. I tried to send the ZT_TONEDETECT ioctl which appeared to take OK but I never get any dtmf events.

I next tried to put the card into data mode and simply read the pcm data from the card and pass it through the dtmf detect logic in spandsp, also no luck. I tried putting the card into ZT_SETLINEAR linear mode, no luck, I then tried it in non-linear mode, both a-law and u-law, passsing each byte through the alaw_to_linear or ulaw_to_linear functions (1 byte=2 bytes) and no luck.

I am probably missing something simple but could use a nudge in the right direction.

Thank you for any assistance you can offer.