I went to site Thursday night with an ISDN-PRI tester. I jacked into the monitor ports on the CSU and configured the tester so I could selectively listen to Eq audio and network audio.

Then the fun began with calling in, calling in, calling in, calling in. Could not duplicate trouble. I went back Friday morning and finally was able to get a similar trouble. I called in and there was no audio in either direction. I placed the call on hold so the system would broadcast music on hold and thankfully heard it on the test set so I know the system is doing its thing.

We left the call nailed up while the customer called Level 3 and tried to get them to help. We got the same old run around about the D-Channel setup being good which was never the issue. When we explained there was no audio on a B-Channel, you could hear the deer in the headlights look. The tech was going to open a ticket with T-Mobile (where the call originated from) but I think that is a stop gap.

We tore down the call and, for grins, I tried to replicate it. I did. We then tried 150 test calls from an AT&T wireless with no trouble. I was also not able to recreate the trouble for the rest of my visit from my phone.

I feel much more confident that this is not an NEC issue and I think I won the customer over on my side because I at least visited the site and performed some meaningful testing and could demonstrate logically what was happening.

Michael Meyer