sundance-communications.com/forum Forums TDM Business Telephone Systems NEC Telephones & Systems DSX 160 Intramail

I assume the channel bank is on-premise. If so, make sure your loop length is set to short (PGM 3103-03). The DTMF may also be hot, so you may want to try lowering your Rx gain a few dB (PGM 3103-02).

I have had this same issue with a DSX 160 for the past 4 months (since install). What I have done so far..

Adjusted sidetone settings (loop length and transmit/receive gains) to the point of ridiculousness. That was NEC's solution and it didn't work at all.

Installed loop current limiters. The CO is providing hot lines and I hoped to reduce the current to acceptable range without losss of sound level. Didn't work either.

Replaced all cards in the switch. Everything but the backplane. Also didn't work.

I am now dealing with a reticent and unknowledgable CO representative. I had to explain to him what DTMF meant and what it represented. I think they are giving me out of frequency DTMF. I know that they are not even providing CPC and have proven that, even though they insist they are providing a 500ms signal.

I'll let you know if we find a solution.

Are the cable pairs physical (copper loop)?
Several issues to look at here.

Loop extenders
Pair gain device
Is it a T1, or Pri?
Mux.

What is providing your dial tone, and by what
means is it provided?

The cable pairs are physical copper. I'm not sure about the loop extenders. They have a T1, no PRI. As primarily a programmer, I'll have to bring the rest of those questions up to the technician when we are on site. I'm going out on Mondday to:
1) Replace the Intramail to get them back to their originally purchased card size.
2) Loop length is set to long, so I'll give it a shot at short since I know the Adtran is right there in the same room as the KSU.
3) I'm thinking of lowering the receive gain, but since I recently had to increase it since cell phone DTMF was very rarely recognized, I'm a little leery about that one.

Did you ever resolve this issue? I'm curious because I'm still dealing with my installation that is experiencing similar problems.

I now have a PCGrabber hooked up to the lines and I can see that the correct signaling is coming in. But breaking through the AA message and/or getting routed to the correctly dialed extension are still problematic.

It actually is not resolved yet. We have developed a host of problems on their lines, though and are embroiled in heated disputes with the carrier. I believe the Adtran is being replaced next.

Please do post anything you learn, as will I.

I have had two conversations this morning with NEC Unified. The biggest suggestion they had was to go with the extreme transmit and receive gain adjustments (-14, -14, short loop).

They are also suggesting that the DTMF TWIST is out of whack by greater than 7%.

Great! Now I'll need to spend more money obtaining a device that will test the db levels of each of the tones in DTMF before I can hit the carrier with that one.