Showing results for 
Search instead for 
Did you mean: 

Multiple ISDN BRI lines with UC560 - customizing caller ID

Level 1
Level 1


I installed a UC560 connected to six ISDN lines representing three different companies(let's say their names are A,B and C) which share their IT infrastructure. Depending on the intern extension, appropriate caller ID's should be used (three different numbers), I tried to configure this via CCA.

For example I configured company A's number to be shown when extension 10-20 are calling and company B's number to be shown when extensions 30-40 are calling. Company C's ISDN line is basically never used as the provider is permanently forwarding incoming calls to a mobile phone.

At first everything worked as expected, but from time to time wrong caller ID's are shown when calling numbers outside the company. For example when extension 14 was calling, which was configured to show company A's caller ID, company C's number is shown.

Did I configure anything wrong or is the caller ID influenced by the outgoing ISDN line? (All lines are in the same PSTN Trunk "ALL_BRI") Do I have to configure seperate PSTN Trunks for every ISDN number? (Which would lead to fewer call slots being available as company C's line would never be used)

Kind Regards,


8 Replies 8

Level 4
Level 4

Hi Rainhard,

In my experience the service provider can restrict what caller ID is sent out to only the DDI numbers that are assigned to that line.

So if company A’s DDI’s are assigned to ISDN#1, and Company B’s DDI’s are assigned to ISDN#2 etc. then if company A makes a call that leaves the system via ISDN#2 the service provider could replace the caller ID with the default number from ISDN#2?

I would check with your service provider to see if they have any restrictions configured. If they do you many need to configure your system to force the different companies to makes outgoing calls via a specific line.

Hope that helps!


How can i configure the UC to make outgoing calls via a specific line, depending on the internal extension? (For example Extension 10-29 -> BRI 0/1, Extension 30-39 -> BRI 0/2). At the moment, the UC seems to randomly choose a BRI line for outgoing calls, which results in wrong Caller IDs being shown if an inappropriate line is used.

This is asked quite often, so if you search the forum you should find answers.

It's true that there are many similar questions on the forums, but I've now searched for almost an hour and didn't find any solution to my specific problem...

and many others similar threads

Level 1
Level 1

Hi Rainhard,

Did you have any chance with this old issue ?

I have the same problem with my UC560. If both channels of ISDN 1 are used, the systems picks up ISDN2 and so on... I tried to solve this using PREFERENCE but it got worst as all companies used the same line with higher preference when a channel is available. So question is : How to make the UC not to hunt to a different ISDN line when the dedicated ISDN line is used ??? Any hints are wecome.

Thanks for everything

Jargogne GRAND

Hello Jargogne,

Yes, I solved the problem using COR-lists. There's a .doc somewhere on the forums explaining to configuration by using a simple example (search for "UC500 COR"). Anyway, here's a sketch of the configuration I used:

dial-peer cor custom

name company_A
name company_B


dial-peer cor list call-company-A

member company_A


dial-peer voice 5000 pots

trunkgroup TRUNK_A

corlist outgoing call-company-A


! for each phone of company A

ephone-dn 582 dual-line

corlist incoming call-company_A


The configuration is a little confusing, I think the original purpose of COR is to restrict calls to certain numbers for a group of phones. However, this works perfectly fine to restrict phones to use just one  specific outgoing trunk.

Kind regards,


Hello Rainhard,

First of all thanks a lot for your answer and sorry about time it took to react.

I have a UC560-T1E1-K9. I use the T1/E1 for PRI and a VIC2-2BRI-NT/TE installed in the slot where I have 2 ISDN lines connected. I had tried to implement the COR thing. And it worked as long as a line is available within the TRUNK_X group. 

Problem is that when 4 users from the VIC2-2BRI-NT/TE take all the 4 ISDN channels and a 5th user makes a call, the system automatically assign him a line from the T1/E1 instead of giving him a busy signal !! So the system is hunting from TRUNK_A to TRUNK_B instead of hunting within a trunk group..

Do you think that it has something to do with the version I use ? (version 15.1)

Many thanks and best regards.


Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: