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Hi everyone,

I have 1000s of locations running isdn as backup with C-DOT Exchange.

Im facing problem often with these SVCs that call will get disconnected with in 20 secs.- Normal call clearing

I have solved this issue by getting a switch port reset at exchange(provider) or by changing the port at exchange(Provider).

Some how i reached to a conclusion that this is a provider issue.

Have anyone faced this issue (Especialy in india - BSNL).

Is there any workaround / solution by tuning timers or changing some configuration in router?

please help.


Re: ISDN-Cdot


we did face similar kinda 20sec normal clearing issue especially in northern parts which got resolved after proper coordination work with the respective exchange personnel.

still remember the reason being told as data channel problem though voice channel works with ISDN, data channel needs to be opened etc.,

would suggest to capture the logs during the call clearing with the disconnect codes which mite help you out to nail the issue.


Re: ISDN-Cdot

Hi Rajiv,

I still remember the days when we used to be head-on with BSNL/MTNL guys. Most of the time, its a provider issue and got solved only after taking with them to a considerably higher level and after a long dispute.

ISDN-BRI in India is the most untrusted Data Network.

Best would be if possible change the provider i.e. Reliance or Bharti. But sometimes if the option is not available, as Prem said, get as many logs as possible and talk to a senior person at the Exchange who can be of some help.

All the best,

Kind Regards,

Wilson Samuel

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