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ISDN PRI to PRI dial backup

I am testing using ISDN PRI circuits for dial backup (both ends). The problem is the call comes in as a voice rather than a data call. Is there any parameter in the calling router that can force the call to be a data call? Otherwise I will need to go back to the carrier and have them limit the calling PRI to data only, if they can (will) do that.

The calling and receiving dialer interfaces are configured for PPP. When I call in from a BRI circuit it works fine. The receiving router is configured to handle both data and voice calls for ISDN and Analog dial backup.


Re: ISDN PRI to PRI dial backup

I don't know if there is a way to manually set the bearer capability on the calls. If the call is initiated as a DDR call NOT using any type of internal digital modems or anything like that the bearer cap should be data. If its voice it could be a bug, but I would check w/the carrier. The debug isdn q931 will show what the dialing router is transmitting as the bearer cap, if the receiving router is seeing some thing different the carrier is changing it.


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Re: ISDN PRI to PRI dial backup

Thank you daniel,

The calling router definitely shows the call type as DATA in the debug messages. I have opened a ticket with Cisco to be certain there are no bugs. The carier calims they are just a 'pipe' and it must be the router that is the problem. I am not so sure but I don't know enough about PRI service to make a judgement.


Re: ISDN PRI to PRI dial backup

Do you happen to know the IOS Ver on the calling and called routers /


Community Member

Re: ISDN PRI to PRI dial backup

The version is 122-17, however, the issue was resolved by the carrier. We managed to get to the right person in their support structure who understood the entire situation. We had requested a 'special' agreement to dial into an 800 number for data calls. The carrier configured it for voice only. We later found that they will not allow PRI to PRI 800 data dialing. We needed to convert the receiving service to a 700 number.

Thank you for your responses...

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