PSTN lines do not hang up after calls are finished

[Saruul]

I have BCM400 running on BCM3.0, no any patches applied.
Our PSTN lines get blocked (giving busy signal) at following situations:
1) After successful call using DISA, the PSTN line doesn't disconnect automatically until I physically disconnect.
2) When user activated Call Forward (F4) feature to PSTN or mobile numbers, after call is finished, PSTN line ( which forwarded the call to mobile) stays occupied and doesn't disconnect until I physically disconnect.
3) When outside BCM call is transfered to another outside BCM number, after the call is ended, the same situation is repeated.

Please help me to find solution to this problem.

 

[3Sixty]

Have you analogue lines?

If so check the the lines are set to loop guarded.

Marshall

http://www.marshallshouse.co.uk

 

[Saruul]

Yes, those lines are analog. what u mean by 'loop guarded'? My CTM8 and CTM4 modules type are set to Loop. Is there anything I should do to make it 'guarded'? All lines are set to Supervised and disconnect timer are set to 260ms. However the above problems occur, don't know what's the problem.

Pls help.

 

[3Sixty]

Ok I guess they call it supervised where you are. Can you confirm the clear down disconnect timer is correct with your network provider.

Marshall

http://www.marshallshouse.co.uk

 

[gecko202002]

Confirm with the carrier that there is disconnect supervision on the lines. If you are a channelized T1 you may need to drop your disconnect timer down more.

 

[Saruul]

Disconnect timer is not the issue, I tested it even bringing it down to 46ms, there is something else need to be tuned.

 

[Saruul]

Mongolia Telecom Company doesn't provide such supervision service to any of their analog lines. They say that there are many internet calling card service providers, who use the similar functionality of DISA. None of those company complain about supervision, as per MTC. I talked one of calling card company and they say that their lines are normal MTC analog lines like ours and they set the configuration on their PBX to make lines disconnected. Their system is different than ours, probably our office is the only one who has Nortel BCM in Mongolia.

Any idea why would lines blocked? Thanks in advance

 

[3Sixty]

Try switching the supervision off. They may not have supervised lines but they would have to send a clear down disconnect signal to the phone system and vice a versa. I would ask them for this clear down disconnect time and confirm the BCM is set the same. Is the BCM set to the correct region.

Marshall

http://www.marshallshouse.co.uk

 

[Saruul]

Turned off supervision. When tested with above situations the lines got blocked and wouldn't disconnect, even unplugging lines from module wouldn't help to disconnect them. So I had to change the supervision status back and reset CTM modules.
Also, if I change it to unsupervised, answer mode to Auto or Manual and answer with DISA are hidden.