SIP Route Pattern – Prefix Digits (Outgoing Calls)

[Bill]

I am playing around with SIP Route Patterns in Call Manager and wondering if I can prefix digits to calls that use it.
It’s CUCM version 14.0 SU3.

I see there is a field to enter the Prefix Digits for Outgoing Calls.
But it does not seem to do anything when I configure it.

There is a note that says this:
The appended prefix digit does not affect which directory numbers route to the assigned device.

I don’t know exactly what that means.
Probably means that it doesn’t do what I want.
But what then is the purpose of the Prefix Digits field in the SIP Route Pattern?

Wondering if someone might know how I can prefix digits to the user portion of the SIP URI that matches my SIP Route Pattern.

Thanks

[b.winter]

It does what it says: prefix the calling number.

BUT:
It depends on the line settings and the parameter "Calling and Connected Party Info Format" in the SIP Trunk setting, what will the user-uri be (a number or an uri).

Per default, the parameter is set to "Deliver DN only in connected party".
Therefore, the calling uri will be a number which then can be prefixed.

If you set the parameter to "Deliver URI only in connected party, if available", then the calling uri can either be a number or an uri.
Depends if the directory number has an Directory URI assigned (e.g. for Jabber).

An URI won't get prefixed, because it's not a number.

[Bill]

Thank you for the information.

I wasn’t aware of the dependency in the SIP Trunk.
I tried changing that setting, but did not make a difference.

I am trying to modify the user portion of the URI, which is the DN.
But doesn’t seem to make a difference no matter what I do.

Without going into too much detail, I am trying to modify a HELD call from a Webex device making a 911 call.
HELD is the protocol Webex uses when making a 911 call to provide geolocation info. The HELD protocol uses the SIP Route Pattern instead of just dialing a number.

I want to modify 911 to be ###911, so when it reaches the Cube, I can distinguish it from a regular IP phone making a 911 call.
The 911 call paths are different depending on which device makes the call.

I added the ### as prefix digits, but when the call reaches the Cube, the prefix digits are not there.

[b.winter]

It's not working, because you want to modify the called number.
But the pattern only modifies the calling number, as stated in my first message and also the settings in CUCM tells you that.

[Bill]

Well Duh. I am a bonehead.
I looked at that I don't know how many times thinking it was "Called Party".
Obviously that is not going to work,
I did find a workaround for the Cube.
I am matching the incoming call using "Destination URI".
This seems to have solved my issue.
Thanks

[b.winter]

No need to be a bonehead. I think, everyone knows this "issue", so "see" not clearly ':)'
Great it got fixed in the end.

[Bill]

Thanks.
I think I saw it that way because that is how I wanted it to be.

So I looked right past how it really is.

[Steven L]

we all do that sometimes...in more than just Cisco/IT matters...:)