We have an Asterisk 1.4 server with a multi-FXO port Sangoma telephony card installed that is receiving inbound calls from our customer’s on-site equipment. Our customer’s technician informed us that he can provide only two options to indicate call hang up – “dial tone on disconnect, or a standard hard disconnect”. We’ve tried several different Asterisk settings and neither option is being recognized, so the line stays open until a timeout is hit.
When we tried “standard hard disconnect” we saw the voltage sit at 51 volts while waiting for a call, drop to 7-9 volts when the call connected, and then remain at 7 after a hang up. No polarity reversal was noted either.
We’re currently receiving an audibly recognizable dial tone, but Asterisk isn’t detecting it.
Does anyone have any suggestions?