Linksys SPA 3102 not detecting hang up from Asterisk FreePBX

[rajeevraj22]

Hi,

I am forwarding calls from my pstn to freepbx using SPA 3102 (pstn to voip gateway). I have programmed asterisk to disconnect the call. It seems asterisk is working fine and disconnecting but pstn user still hear the call ringing. How can i make the call disconnect?

Thanks,

Rajeev

[ildefonso_v1]

Hi 

I am having exactly the same problem with freepbx. Everything works as expected except when asterisk or internal phone hangs up an incoming call from FXO port, the spa does not hang up the line until 30 seconds after. 

I have tried to change the Disconnect detection method with CPC=yes with different values for min CPC duration 0.09,0.1,0.2,0.3,... , with Polarity Reversal=yes, with Disconnect tone from Spain 425@-10,425@-10;.8(.2/.2/1);(0/.4/2), but any of these changes worked. 

I activated the debug log in the SPA 3102, I see when spa line is Idle the curren Voltage is 52V, When a call is done the voltage is -7V. When I finish a incoming call from any internal extension or from asterisk the voltage is 52V again, but the call does not hang up in the other side. After 30 seconds I can see in the syslog POL REV -47 52 then the call hangs up in the other side. 

I would like to know how can fix this problem. 

Thanks in advance!

[Dan Lukes]

It's not be possible to solve issue described by rajeevraj22 in first message. According description, the incoming call has not picked up  ("pstn user still hear the call ringing"). Unfortunately, POTS signaling protocol doesn't allow to reject the incoming call. SPA3102 can either pick up call or ignore ring signal on POTS line. In the second case the calling user is hearing ring back tone until he hang up or call setup timeout occur.

Despite your's (ildefonso_v1) problem seems not to be same (your call has been picked up first) there may not be solution available as well. CPC stands for "Calling party Control". CPC is signal sent from terminating PBX to called phone to indicate that the calling party has hung up. Terminating device (SPA3102 here) is recipient of CPC signal, not the source. E.g. CPC is related to opposite signaling direction that the one you are speaking about.

The call disconnect from end device to PBX is signaled by high impedance of end device.

I see when spa line is Idle the current Voltage is 52V, When a call is done the voltage is -7V. When I finish a incoming call from any internal extension or from asterisk the voltage is 52V again, but the call does not hang up in the other side. 

OK. So idle line voltage is 52V. According your description, the SPA3102 disconnect properly from line on end of call (voltage rise to 52V). If the call doesn't disconnect, then it's not matter of SPA3102 but matter of terminating PBX.

The behavior like it is not so common in current phone networks, but older phone network switches allow no hangup from called side at all. Only caller is allowed to terminate the call.

All at all, you can't solve the issue from your side of wire. If terminating PBX is not willing to disconnect call immediately, you can do nothing with it. Ask your Telco operator for support. The behavior of particular line may be configurable. But don't put so much hope on it.

After 30 seconds I can see in the syslog POL REV -47 52 then the call hangs up in the other side. 

It is the CPC signal from PBX to you. The PBX considered the call is over and is signaling it to you.

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