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Caller I.D through PSTN

A customer has 30 DDI's, they want these DDI's to be displayed to the called party when going over the PSTN as opposed to just the main number being displayed. Teh problem is that no matter what DDI phone makes an offnet call only the main number is being displayed. We have CCM 6.1.

can anyone explain at what precise time the output of debug isdn Q931 is taken? is it at the exit point of the router's E1 interface after all translations etc, is this the command that can confirm that is the last calling number info before the telco receives it?

I can only assume that the carrier, in this case BT (UK) is just using the main number. Is this correct?

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Re: Caller I.D through PSTN

Yes, the debug output reflects the actual message sent to telco.

What can be wrong in your case, beside the calling number itself, is the type/plan IE.

If it is not set right (can't remember now what BT wants, but should be the same as for an incoming call), the calling number will be considered invalid, and overwritten with the main one.

Hope this helps, please rate post if it does!

Re: Caller I.D through PSTN

You are correct, the number being displayed in the debug isdn q931 is the number that is being sent to telco. If you want your DDI's to be displayed, you need to configure external calling party mask on the DN in question, and then on your route groups, route patterns, and on the gateway, you need to check the box that states 'Use External Calling Party Mask". If the number being sent to telco is still incorrect, you need to check w/your telco to see if the PRI is only set to have the billing number sent on outbound caller id.

Hope that helped

New Member

Re: Caller I.D through PSTN

many thanks for the replies.

its good to have a sanity check, Paolo, when you say setting the numbering plan, where is that actually set and is it just 1 command

Re: Caller I.D through PSTN

Numbering plan is set under the gateway configuration in the call manager.

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