ISDN Voice call and data call

Unanswered Question
Sep 30th, 2007
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Hi all,

I have seen quite many times that in ISDN BRI lines isdn will not fire and will give unfound-B Channel error while debug. But at the same time voice call using an ISDN feature phone is working fine. Since Voice call is fine by vendor is not agreeing that there is an issue. What is the difference between ISDN voice call and data call, in what condition Voice call will work and data wont? please suggest

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Loading. Sun, 09/30/2007 - 23:11
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It is strange. The call type is identified in the q931 setup message by the bearer capability.


88: ITU-T coding standard; unrestricted digital information

90: Circuit mode, 64 kbps

21: Layer 1, V.110/X.30

8F: Synchronous, no in-band negotiation, 56 kbps

Try to make q931 debug (debug isdn q931) when the call fails to see what happens exactly.

Hope it helps, rate if does



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