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New Member

Voice over PSTN solution


Are there any tricky issues with setting up Voice over PSTN with Call Manager 6.1.2, 2801 pstn routers and unity connection 2.1.

My concerns are site to site calls and voicemail (unity 2.1) accesss.

I understand that AAR is required to dial back out of the pstn router when the call goes to voicemail. Can unity still be setup with extension numbers and the inbound digits from the routers get striped to send only the relevant ext number. I also understand that RDNIS has to be enabled or supported by the ISDN telcos.

Any pointers or gotchas?

Many thanks!!!


Re: Voice over PSTN solution

Here is the URL for the Understanding and Troubleshooting Call Routing and Dial Pattern Problems with Cisco CallManager. I hope it may help you


Re: Voice over PSTN solution

RDNIS is not always supported by telco`s. Also technically you do not need to use AAR if you are only doing PSTN for Voice Mail, set up the VM profile as a PSTN number and let CCM route out. IF you are using AAR then set the location, region to 1k so to force it out and delete any AAR text strings so it does not show up on the users phone. Remember the AAR External mask is now separate from the normal External MASK and be aware of how you configure the MASK. If you have national sites, same area codes dialling each other

Site A in France is called by UK but uses AAR so the MASK should be 3315551234 with the AAR group adding a 900 as a prefix however if site B also in France wants to call Site A - PSTN access code 0 , then the same MASK of 3315551234 would be incorrect unless you use translations as the completed AAR number would be 033315551234 -0 PSTN code. It is best to set the MASK as generic as possible and let the AAR group add the necessary codes

UK to France AAR 90033 - Access code from UK 9

France B to France A AAR 00 -Access code from 0

mask in Site A is now 15551234

You may need to reduce this further if there are sites in with the same area code so users dial 0(PSTN)5551234

France B to France A AAR 001

France A to France A AAR 0

UK to France AAR 900331

MASK NOW 5551234

Hope it makes sense

New Member

Re: Voice over PSTN solution

Yup that makes sense..

Can i still use the 5 digit extensions in Unity for each user at remote sites?

I thought i'd strip the inbound callerid number on entry to main site so its last 5 digits route to voicemail correctly..


Re: Voice over PSTN solution

Are you talking about the RDNIS feature, I`m not sure how that would appear

Users in the remote site diverts to central VM - 12125551000 on no answer with a redirected number of 1234 - VM box- I`m not sure the 1234 appears as a "real" number for you to translate. Translating the VM access number 12125551000 - yes depending on how numebr digits the telco sends to your switch. I think the redirected number will be your DN of the remote extension so maybe do a translation not sure though may be via a MASK and translation pattern?????

New Member

Re: Voice over PSTN solution

Thanks. I'm waiting for the Telco to confirm RDNIS first..