Disconnect Woes

Hello all,

I’m having an issue with asterisk recognizing disconnects on my Digium TDM400, which is fully populated with FXO cards. We’re installing our asterisk system behind our company’s legacy PBX (a WIN 440DT, I think). Our PBX was extended with four “analog extensions” to feed the TDM400. Outbound calling via a SIP phone works perfectly.

Inbound calling works well, if the call originates from within the PBX. Upon hangup, we get 20 seconds of “fast busy” then a polarity switch occurs, which asterisk recognizes and hangs up the line. However, calls that originate from outside the PBX (which is fed by a university telephone system, which is in and of itself a large, glorified PBX), never even get a polarity switch, it simply ties up the line until I destroy the channel or stop asterisk altogether.

Disconnect supervision is not an option, as I’ve already spoken with our PBX provider asking about this, and she insists it’s not available on the system. Busydetect and callprogress dont seem to do anything. I’m stuck for ideas, and would love to know if you guys have any suggestions. Thanks in advance!

Kindest Regards,