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How to Disable to call own Extension Number (DN)

Level 1
Level 1

Hi Team,


we have this client that is meticulous they want to disable calling  their own extension number from their assigned phone.


Scenario my IP Phone has an extension 1001,

when i lift my handset (using phone with extension 1001) and dial extension 1001

my extension rings.


how can i disable that?



16 Replies 16


I don't think that you can disable it. But if you want to disable it, as a workaround you can play around with the Maximum number of calls and Busy trigger. but if you make it 2/1, then your extension will not ring and instead, you get a busy tone. but your extension will never get a second call when you are on another call. 



George Sotiropoulos
Cisco Employee
Cisco Employee



This is not applicable.

You may change the busy trigger setting, however this will generally affect your incoming calls and will definite cause problems, rather than solve.



Please Rate Posts (by clicking on Star) and/or Mark Solutions as Accepted, when applies

Jaime Valencia
Cisco Employee
Cisco Employee

And what is their logic behind dialing their own number? how often do they do that? that they need a solution for this?



if this helps, please rate

Hi JV,

This is the weirdest customer that I have handled so far maybe they are comparing the feature on their previous PABX which is Avaya

Let me know if cannot be done of or not



VIP Alumni
VIP Alumni
1) You can use the Busy Tigger to achieve this. 2) You would need a logic of If Calling Number == Called Number then block the extension. Which is not possible to achieve with CUCM itself. You can try to build an UCCX Script for the same. No sure it will workout of not but just a suggestion. You need to question the logic behind the request, What will the achieve with this feature in place ? Thanks, Haris ** Please rate helpful posts

Level 1
Level 1

Hi. You can add extension 1001 to a new partition and make sure the CSS that the phone or extension is assigned doesn't contain 1001 partition.


Please let me know if this helped answer you question. Thanks 

HI Ruslang,

Nice try but I have already done that.. they have actually 800 locals and don't want to go through every locals and create another css per locals

And also css and pt are already in place for call restrictions


1) Your Option is to route call Internal Call to UCCX Script. This can be done by Creating a DN XXXX and call forward all to UCCX Route Point. This DN XXXX will be in Separate Partition and all Phone will have access to this Partition Only. All Phone will not have access to Internal Partition.

PT_Internal : 1001,1002....
PT_UCCX :- XXXX ( Call Forward to UCCX RP)

2) In UCCX Write a Script which will execute logic if Calling Number = Called Number/Redirection Number then drop the call else route the call to to CSS_Internal.
You might need to work more on developing the script to fit the scenario.


Hi Haris,

Good afternoon

Client does not have any uccx?



Then it is not possible with CUCM or CUC. May be if you can write a TCL Scrip on Voice Router might help.


*** Please rate helpful post; Mark "Accept as a Solution" if applicable


Hi Haris,

There is a work around using css and partition

Creating extension per partition and not including pt of the extension.

However this will be horrible to maintain

Because every time that you add a new phones

You will have to re-config the css of other extension in the production to add the partitions of the new ip phones

Which is not a best practice



Yes that is true. It will horrible to maintain.

Why don't you try the Busy Trigger Option ? Set Busy Trigger to 1 this will give busy signal

I am able to find some hope with Unity Connection for your problem. But this will create new problems with caller Id. You need to test it thoroughly 


Basically we will route All the internal call via Unity Connection. You will not be able to use Voicemail Feature with this.

I have tested below may be you need to refine it more for your environment.


1) Create a DN= XXXX in PT_Test and forward all calls to Voice Mail

2) On the Phone Set PT_Test replacing Internal Partition.

3) So Now When say  5733 is calling 5733

            We have Calling No == 5733 & Redirectin  Number = 5733

4) We will create rule in Unity connection which says if Calling No & Redirection No = 5733 Send call to a Test Call Handler which will drop the call. Below snapshots show the configuration. Now you have to add the rule for each and every DN. This will be limited by How many Call Routing Rules we can add in Unity Connection. I was not able to find the limits of that




5)  Now if the User dial any other Extension say 5705.

  In this case   Calling Number = 5733, Redirect No = 5705

  This call will by default will go the Voicemail Box of 5705. You must have Voicemail Box for Each DN. Now you have to disable the default greetings and route call to Transfer Rule of Same voicemail box as below to send call to the DN



Change the default greeting page to play nothing and transfer to same voicemail box.



Update Transfer Rules of same voicemail Box.



===> Make sure to assign Proper CSS to VM Ports/Trunk

===> While call is getting transferred you migh face issue of not hearing ringback or hearing MOH instead of Ringback. You might need to replace MOH with Dummy Ring back tone.

===> Users will not be able to use Voicemail Functionality.


*** Please rate helpful post; Mark "Accept as a Solution" if applicable




Did you try below suggested Option.