Hangup on busy

Hi to all,
I got the following problem:
I have two extensions associated with two different DID(real PSTN numbers).
Receiving calls is ok, no problem, except when they are already talking.
So if the line is busy, the caller does not hear the busy signal, but hears as the called party hangup to him(very bad).
The busy signal comes out, only a few times.
More, both extensions, do not have voicemail.
From the CLI I can see the call receives the busy answer, but the call will be dropped.
Both phones are Grandstream: one BT200 and one BT101.
I’ve set DTMF to rtc2833, and tryed also with inband and sip, without success.

Please, can somebody help me?
Thanks to all

FYI: The dtmf settings have nothing to do with getting or not getting a busy signal.

It sounds like your POTS card is not properly configured but you have not provided any information at all that can help in providing you with any more direction then that.

…I have 2 BRI connected to my Asterisk with a Sangoma A500.
The problem is that Asterisk correctly send the busy signal, which is not understood from the caller over the telco.
I’ve contacted the telco too, and seems that they found a miss configuration on their Cisco 17XX.
May I ask you, what you would check on the BRI configuration?
A specific parameter?

Thanks for you time.

I’m in the US and have never dealt with a BRI, so will be of little help. But also mote that many of the default setups are configured for the US. So if you are in another country you’ll want to make sure that you have it configured for the proper country as signals change between telco systems and countries.

Best thing is to google for asterisk and bri setups as I’ve seen information on setting it up for the UK versus different countries.