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Community Member

convert analog DID to a PRI?

Hi all, the more I research the available hardware, the more confused I get... I'm definitely not a Cisco guru by any means.

First of all, my goal is to convert an analog DID circuit coming from the phone company to a digital PRI while at the same time preserving the "dialed number". The end result would be a PRI with 1 active B-channel, 22 inactive B-channels, and a D-channel containing the signaling including the dialed number. My ISDN phone equipment would then take it from there.

Second, I'm trying to do this as inexpensively as possible...

The boxes I'm currently looking at using are a 2600 series router and/or a MC3810 concentrator. The only reason the MC3810 is attractive is because they're available used for around $100 including a voice-capable PRI port and alternately it looks to be a bit more expensive to add voice PRI capabilities (high density DSP? NM-HDV? AIM-VOICE-30?) to a 2600. The 2600 might still be required though for the analog DID portion. A 2600 router with a low-density voice carrier card (NM-2V) and DID card (VIC-2DID) is affordable but I'm not sure if that's all I would need or if what I'm trying to do is even possible...

I don't have any other Cisco equipment in the picture, so this would theoretically be either a one-box (2600 or MC3810) or a two-box (2600+MC3810) standalone solution.

Any suggestions would be greatly appreciated.




Re: convert analog DID to a PRI?

I am unclear about the analog. Is it going away or not? The MC3810 should work but I would definitely go H.323 with it. Are you connecting this to a Cisco Callmanager?

Community Member

Re: convert analog DID to a PRI?

Thanks, that's a good lead. I should then focus on getting the 2600 to accept an inbound analog DID call and convert it to a H.323 call.

The analog DID circuit coming from the phone company would be the original source for incoming calls, so if H.323 is used between the two Cisco boxes it would look like this:

analog DID -> 2600 -> H.323-> MC3810 -> PRI feeding into our phone equipment.

The goal is to avoid paying the phone company for a true PRI since we really only need one channel, not 23, but we still need it to act like a PRI (including D-channel signaling).

No other cisco hardware or software is involved but someone on another forum mentioned possibly needing to install CallManager Express into the 2600 to handle the call routing. I've also read that the "ix" versions of 2600 firmware can act as a H.323 gatekeeper (is that the same as CallManager Express?).

I'm pretty familiar with how H.323 works in general but I have very little Cisco experience.

Just wanted to check for any negative responses before I actually get the parts and try it. The Cisco docs all look pretty positive but it's hard to really tell without playing with the equipment...


Re: convert analog DID to a PRI?

i would think that to move an analog number to a digital circuit would include changing the "routeIndex" of the DN (DID).

this requires the telco to perform work in their switch(s).

Community Member

Re: convert analog DID to a PRI?

Based on some discussions on a different board, my understanding is that he wants to keep the analog DID because it's so cheap and it has a whole bunch of numbers pointing toward it. He needs to be able to accept an analog DID on one interface and send that call out a PRI on another interface toward a PBX.

The telco won't need to do a thing, but he needs to know what equipment is necessary to pull it off. Does he need CCME to handle a PRI, or could he do this with just the Voice IOS and no CCM or CCME?


Re: convert analog DID to a PRI?

I now understand your scenario a lot better. What you are doing looks very viable. You would not need Callmanager Express on any router to do this. That is only neccessary if you want Cisco IP phones to register with the router. H323 provides all dial plan features you will need.

Community Member

Re: convert analog DID to a PRI?

Many thanks to all! I'll get the parts and give it a try.



Re: convert analog DID to a PRI?

Good luck and please remember to rate helpful posts!

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