atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems NEAX 2000 IPS PRI dropping frequently

A friend of mine, an experienced tech, is new to supporting a NEAX 2000 IPS. Recently the PRI started dropping calls. CenturyLink claims they have checked end to end and not seen any problems, and the IPS isn't showing any alarms.

He's considering trying to change out the T1 card, but wanted to make sure the replacement was compatible. The original card is a PN-24PRTA. The replacement is the same part number, but wondering if there are certain revision level limitations.

Also, I'm looking for any insight to the problem with the drops that started "out of the blue" with "no changes" leading up to them.

Thanks!

Justin

Usually, once it's up, the PRI on an IPS is bullet-proof. The big gotcha in the original set-up that will make it sometimes work, sometimes not, is the ISDN protocol setting. If I remember right, 20 is National, 21 is DMS, and 26 is NI-2.

As you know, this has to match the Telco. But on the IPS... Well, in the immortal words of "Mr. Stuff," the IPS Guru, "The switch is just a little bit slutty. Sometimes it will work for a while with the wrong protocol."

So... If the Telco changed switch types recently, that might be the problem.

Changing a 24PRTA should be a simple swap. You can power it off at the card and do it hot, but I recommend doing a full power down of the switch and then bringing it back up with the new card in.

Remember that the main control cabinet should be first off and last on, so that the main control never knows that the other cabinets went down. this keeps it from generating a bunch of errors that you already knew about.

Oh, one other thing: He should be using an EXTERNAL CSU / DSU. The CSU function that is built into the 24PRTA card is flaky as hell, and mostly doesn't work right.

I agree, the IPS2000 was a bulletproof sun of a gun and if not for the damn voicemail failures 99% of em would still be in service.

I seriously doubt you have a card or PBX issue.

As stated above swapping th card is fairly simple: flip the toggle up, pull the card and put the new one in, flip it's toggle down.
Also recommend an external CSU.

Good luck!

D

For diagnostics, you can try looping the PRI back to itself. You may still see CRC errors with it looped back to the PBX, but it should stay up and run.

Whilst I believe doghart is correct, please check all the switch settings are the same before bringing the new card online. Better yet, work the correct switch settings out for yourself to be sure there wasn't an error with the previous settings that has till now been tolerated by the carrier!

I had a fault once where everything stopped working and it turned out that the carrier had done a software upgrade overnight which made the exchange less tolerant of errors and one small bit of data that was previously tolerated stopped the service from working!