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PSTN hand off with NEC 2400

This may not be the best place to ask, but I'm hoping to find someone who has worked with NEC 2400 series switches.

We have connected our 2400 to both ports on a VXB board in a 7206. I've used both T1 and after some hassle PRI configurations. Both integrations work fine for internal toll-bypass, but only the T1 seems to work when the destination number is external to our network.

For example- I can call home from a 7940 if the current integration is T1. If I switch over to using a PRI, I get an error "Unassigned number" back from the NEC. Calls to extensions hosted on the NEC work fine.

While it is clear this is a problem with the NEC configuration, I haven't been able to get help solving it. As soon as I say we have the switch connected to a router, the blame game starts.

So if anyone is experienced with NEC systems, and can provide guidance, I'd appreciate it. I also know this would be much easier if I were just to use the 7206 as our PSTN gateway, but the migration plans require the NEC be used for some time to come.


Re: PSTN hand off with NEC 2400

I can definately say that our integration to an NEC 2400 did not work until we placed an AS5300 in between our connection from the PBX to a 6608.


Reason being, NEC MUST (and I stress MUST) connect to an e&m port that supports "feature group b". The only Cisco gateway that supports feature group b is the AS5300. Again, I stress this is the only configuration that will work.

Community Member

Re: PSTN hand off with NEC 2400

OK, I had the management for the 2400 dumped in my lap, and I've picked up more than I every hoped to know, but I have no idea what "feature group b" is.

I can get the 2400 to tandem switch a call if the integration method is with a T1 (24DTR card). Using a PRT-B fails. So I don't think the problem is with the router or dial-peer configuration. I'm waiting on a call back from a NEC engineer.

Thanks for the info though. It may help me direct the engineer to the answer, even if that answer is that it will not work.

Community Member

Re: PSTN hand off with NEC 2400

The solution appears to be in ARTD for the routes connected to our Cisco. By setting CDN 66 to value 15, we can now tandem through the NEC.

I put this up here in case it might help in another integration.

Community Member

Re: PSTN hand off with NEC 2400

We have our CallManager connected to our NEC2400 directly via a Cisco 3662 Router running the HDV double PRI modules on MGCP. Have you tried this config?

had some troubles initially on the NEC side - but working great - especially if the Cisco side is network as our 2400 does a lousy job being the network side and we get some channel freeze-ups in that config occasionally.

- Ken

Ken Johnson

LeTourneau University



Cisco IP Telephony Users Group

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