Extension and direct line for IP 7906 and 7911

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May 22nd, 2008
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I have a CCM 4.1(3) and a Voive gw 2801 w E1 card (VWIC-1MFT-E1)

How is it possible for phones 7906 & 7911 (one lines phones) to configure in addition to the DN (exemple 5050) a direct line. So that the user can be reached internal by his DN 5050 and be reached from external through a direct line (exemple 30313233).


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nicocerti Wed, 05/28/2008 - 06:26
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Hi Dominique

First, it isn't possible to configure more than two lines in Cisco 7906/7911 phones.

But there is a way to achive what you want:

If you have a E1 PRI connected to the router, it sends some digits when there is an incoming call, for example: if the PRI telephone number is 3552000 it sends 2000 to the router and you can use this 2000 to redirect the call to one extension. The E1 PRI service also has DID (Direct inward dial) it means that additional to the 3552000, the caller can dial from 3552000 to 3552099 and the PRI sends the last 4 digits, I mean if the caller dials 3552020 the PRI sends 20202 to the router.

Your solution is to find out which digits the E1 PRI sends to the router, you can do it by using the debug command "debug isdn q931" and make an incoming phone call, then you choose a phone number for the person, in your example could be 30313233. And finally you configure the command "num-exp 3233 5050" so if the caller dials 30313233 the E1 PRI sends 3233 to the router and then the router change the called number to the 5050 and the user has a direct phone number.

I hope it helps.


dom.a Wed, 05/28/2008 - 13:50
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Ok, this exactly what i need !! In my case the E1 PRI send exactly the 04 last digits to the router (when i configure 3233 as an extension for a IP Phone, it can receive call from 30313233).

Could you send me a document which show how to configure it step by step ? i guess this configuration is to be made in the Voice Gateway ?


nicocerti Thu, 05/29/2008 - 07:59
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The documents I have are very large and very general. But I can give you a step by step example:

1. Lets say we have a E1 PRI conected to the router, and its PBX number is 3502000. it also has a DID service from 3502000 to 3502099 and it sends the last 4 digits of the dialed number. for example, if the caller dials 3502010 the PRI sends 2010 to the router. lets also say that you want to redirect the DID number 3502010 to the extension number 5500 (7911 phone)

2. your router must have:

!incoming dial-peer

dial-peer voice 1 pots

incoming called-number .



!outgoing dial-peer

dial-peer voice 2 pots

destination-pattern 0T !this is the pattern of the outgoing calls

port 1/0:15 !this is the port of your PRI

!a dial-peer pointing to the call manager

dial-peer voice 3 voip

destination-pattern 55..!pattern of the extension range of the site

session target ipv4: !ip of the CCM

!the translation of the number 3502010 to the extension

num-exp 2010 5500

We also assume that the E1 PRI and the IP connectivity are working.

a very good voice command reference:


I hope it helps



dom.a Sat, 06/07/2008 - 06:29
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I have configured the voice gateway as you mentioned but no incoming call can reach the designated phone. See in attached the config of the router.

I have also run a 'debug isdn q931' when attempting to make this incoming call, the results says that 'Unallocated/unassigned number. The call reachs the voice gw but it cannot allocated it to the phone.

Pls helps !!

dom.a Tue, 06/10/2008 - 03:17
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As i said in the latest reply, this configuration does not work, nothing happens. I think it because i'm using a MGCP voice gateway ? to be confirmed.

I have rather configured translation patterns into the CCM and it works. But now the problem i have is that sometimes (frequently) when the phone receive a call from a external caller it rings but we cannot hear anything and few minutes later (exple : 30 mn later) everything is good !!

This issue happens even if i removed the translation pattern and put the last four digit of incoming number as the extension for the phone.

I don't know where is the problem. Could you please help !!


nicocerti Fri, 06/13/2008 - 14:18
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I had the problem you describe when the interface and its peer work in 10 half.

check and let me know.

dom.a Fri, 06/20/2008 - 03:56
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Hi Nicolay,

Do you mean the two Ethernet interfaces : voice gateway and CCM ?


dom.a Fri, 06/20/2008 - 07:43
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all the ports of the LAN switched where CCM and voice gateways are connected are on duplex full mode...

Serious issue for me, need urgent help if someone already meet this issue, pls


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