Is there a way to temporarily mask an outbound caller ID from the IP phone

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Aug 8th, 2008
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We are on CallManager 5.1. We are getting harrassing phone calls and I was wondering if there is a way to enable a temporary mask on outbound calls?

I can make a blanket phone number mask change in CallManager, but is there a way to punch in a code from an IP phone to change the mask temporarily if you know you are calling an irrate person that you don't want to get your direct inward dial number?

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Overall Rating: 4.8 (3 ratings)
Michael Owuor Fri, 08/08/2008 - 05:28
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Hi James,

Since *67 is the common way of restricting caller id information, you could try this:

1. Create a new Route Pattern *679.@

2. Calling ID Presentation: restricted

3. Calling Name Presentation: restricted

4. Discard digits: predot

If you are using Route Lists and Route Groups, add the restrictions there, as they override what's on the Route Patterns.

Hope this helps.



james.fredricks... Fri, 08/08/2008 - 06:51
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I think that will work, but I am running into an issue.

My carrier needs to have all outgoing calls coming from "authorized" numbers, that is to say, numbers that we own. Unless I check the "Use Calling Party's External Phone Number Mask" checkbox or input a masking number in "Calling Party Transform Mask" the carrier will not complete the call because it doesn't see a proper originating number.

When I do check the box or input a number as noted above, the "Restricted" settings for "Calling Line ID Presentation" and "Calling Name Presentation" have no effect and the call goes out with the caller ID intact.

Am I missing something?

Michael Owuor Fri, 08/08/2008 - 07:29
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Hi James,

Is the route pattern assigned to a Route List or directly to the outgoing gateway? If to a Route List, remember to add the restrictions there.

When you specify that the CLID and CNAME should be restricted, CUCM still sends the information, but with a flag in the Q.931 messages that this information should be restricted. The carrier's switch should then honor the flag and not present it to the called party. So of interest would be whether the or not the call is actually being flagged as 'restricted' when it leaves your gateway. Do you have the option of collecting the output of debug isdn q931 when placing a test call?



mhering8650 Fri, 08/08/2008 - 09:03
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Is this a SIP trunk or PRI?

If its a SIP trunk some carriers require that you send the outbound CLID with the call setup messages otherwise the call will fail.

If this is PRI you need to call your carrier and have them change your PRI so you can completely control or restrict CLID...

However, Some carriers in the US won't allow calls that don't present valid Caller ID. But usually they will override it with a default number in that case.

What happens if you change the CLID to just present the digits 1234? does the call still fail?

james.fredricks... Fri, 08/08/2008 - 10:48
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My carrier informed me that they will pass *67 for blocking CLID. After that I just had to set up a translation pattern for local and LD and I was good to go. Hoot hoot!

Thanks for everyone's help in talking me through this.

Michael Owuor Fri, 08/08/2008 - 11:03
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Hoot hoot! is right :-) Thanks for the update James.

Happy Friday!




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