System not disconnecting

[andykeen]

Hi all

I have an issue with what I think is the 4104 and 4108 grandstream or the 3cx- not sure.

I have managed to replicate the issue in that when I make a call into the system and, for example, get to a digital assistant message and then end the call the line does not disconnect and in fact the 4104 and the 4108 line led remains lit.

It seems to 'time out' after a while and frees up the line, but during this period the line remains engaged.

It's as if the 'systen' has not recognised that the caller has hung up / disconnected.

Does anyone have any idea where the issue lies and offer any advice please.

Thank you and regards
Andy

 

[leejor]

There are only three methods that an analogue gateway has of knowing when a PSTN caller has hung up (and 3CX is still off hook)....

A signal ( current reversal or a short disconnect) if, that is supplied by your phone company, some do, some don't.

Silence detection, this is usually based on the time of silence (one direction or the other, or both), and if you are not careful can cause low volume calls (calls put on hold) to drop.

A disconnect tone sent from your phone company when the line has been off hook too long. This has to be set up to match the tone used in your area.

You will have to "experiment" with these to see which works best in your case.

 

[andykeen]

Thanks Leejor I will check these out.

 

[AndreasA_3cx]

Hello,

Any PSTN gateway has a section in the configuration where you can set the tone frequency.

If a gateway does not release a call on disconnect it means that the gateway is not recognizing the frequency signal of a BUSY or END_DISCONNECT.

This means that your telco is sending a busy signal but the grandstream is not understanding this (because it is not properly configured) and is passing this busy signal as NORMAL AUDIO keeping the call connected.

Resolution

Contact telco
Ask them for busy or disconnect frequency tone
Match this data to something that the grandstream understands and put it in the grandstream configuration.