CUCM Express SIP trunking question

Unanswered Question
May 20th, 2010


I do not do much with CUCM Express so would appreciate some help with the following.

Is there any licensing requirement on CallManager Express for connecting to the PSTN via a SIP trunk? (thinking that there should be if you need CUBE licenses to connect CUCM to a SIP provider).

Is there a DSP requirement for SIP trunking? If I use G.711 between IP phones and G.729 to the SIP provider will I need DSPs for transcoding?


I have this problem too.
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Abu Hadee Thu, 05/20/2010 - 16:04

Hi James,

I'm not sure about the license requirement. If you use CME and SIP Trunk, then the it is not cube functionality. So you do not need CUBE license.

Regarding the transcoding, you do not need transcoding. Because IP Phone supports both G711 and G729. So when there is call between IP Phones, it will be G711. But when calls are coming from PSTN over sip trunk, it will use G729. Just make sure you have SIP Dial-peer to/from PSTN SIP Trunk configured only with G729

Hope this helps.


- abu

James Hawkins Fri, 05/21/2010 - 02:34

Thanks Abu,

There is nothing about licensing for SIP trunks in the CUCME ordering guide so I guess that you do not need anything - I just expected Cisco to want to charge for this functionality (getting cynical in my old age).

The codec response makes sense. I would guess that transcoding would be needed if I had a Unity Express module installed as that only support G.711?

Abu Hadee Sat, 05/22/2010 - 18:41


You are right, if you have CUE, then you'll need to have transcoder registered to CME itself


- abu

gabiulici Thu, 02/12/2015 - 23:42

Hii guys,


I have Cucm10.5 and 2 voice routers 2921 and 11 E 1 lines and I want to make a SIP trunk with my provider in order to not use anymore the E1 lines. Any ideas if i need licence or something extra in order to create the connection.


Can i create directly from cucm or i have to create the SIP directly on the router ??



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