We have an SX200 MX Controller running several cabinets, and a PRI card. The end user has had several problems in the past with PRI cards, and would prefer to use an NSU instead.
The problem is that once we get more than 30-35 simultaneous calls up through the NSU, all callers start to hear crackling and interference. We've tried choosing trunks 1 thru 46, and also 46 thru 1, but still have the same results. Using the same CIM connections, the PRI card works fine 100% of the time.Any suggestions?

DSP resources???

We've got a Quad DSP installed, and I would've expected no connection at all vs. noise?!?

Embedded card in controller.

Second Mingo... Have had numerous problems with PRI cards and NSUs but haven't had an issue (yet) with the embedded. Of course if you are out of MMC slots disregard previous transmission.. LOL!

What DSP package do you have selected in Form 4? Believe it or not had an issue with this before. It caused weird problems.

Because of the configuration, the 2 MMC's are being used for expansion.

Did you check option 132 in form 4?

It's set to Analog 1, and we have a Quad DSP installed. According to the chart, we should be able to support the config. we have programmed. The crazy part is that it works fine with the PRI Card.

You may want to put a cheap adtran csu in front of the pbx I would also check the status of the circut and see if you are taking any slips.Usually if you are picking up static on a pri you will see some slipping.

You may aslo want telco to intrusive test the circut after hours and see if they see an issue.