SPA3102 does not detect disconnect tone

This might be in the wrong topic, so feel free to move.

I’m having a bit of trouble trying to get my Linksys SPA3102 to detect the PSTN disconnect tone that is played when the incoming caller hangs up. Everything else on the device is working perfectly. It is connected to a TalkTalk (BT) landline in the UK. I’ve been googling around for the past week or so and tried most of the things that I have found.

I’ve recorded the disconnect tone and measured this at 395Hz at -20, changed the string but no luck. I have been able to get hold of a patton box to also test with and if I set it to detect the busy tone, with the settings below, it works. I have also tried inputting the busy tone string into the linksys but also no luck.
I think I’m missing something obvious here, so any help is appreciated.

Linksys config:

Patton busy tone config:
1: play 375ms 400Hz 0dm
2: pause 375ms

Disconnect tone recording:

If anyone can point me in the right direction with this then that would be great. I’m starting to think I have a faulty unit.

I don’t know whether the SPA can detect a continuous disconnect tone. Your setting looks correct. Try removing the space after the semicolon, though it’s unlikely to help.

In most systems, PSTN Disconnect Detection is just a backup mechanism, since calls will normally disconnect from the VoIP side. If that’s not your case, please explain.

Possibly, the TalkTalk box does interrupt loop current upon disconnect, but for a shorter interval than your Min CPC Duration. Try setting that to e.g. 0.2 seconds.

If neither Disconnect Tone nor CPC is workable, I suggest detecting long silence. If you stay off hook after a disconnect, does TalkTalk play the disconnect tone forever? If so, you won’t be able to use silence detection on the PSTN side. Otherwise, set PSTN Long Silence duration to e.g. 600 (10 minutes), which should cover the case where you are on hold and the remote party does not have hold music. On the VoIP side, you might use e.g. 3600 (one hour), to handle the situation where you call into a conference but only listen.

Thanks for your reply. I don’t think the line does CPC for disconnection. I’m not sure how long TalkTalk play the tone for before clearing the line, although I know its more than a few minutes.

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