sundance-communications.com/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems Mitel 3000 analog line gain

Just installed a Mitel 3000 with a single 2-line POTS card installed in the system. I'm noticing a huge amount of gain (background noise) back in my ear when calling out on the POTS lines. These are standard copper (GTE/Verizon/Frontier) lines, not VOIP or T-1. When making internal station to station calls the phones sound great. The noise is not an echo as much as the phone handset seems to be picking up every sound in the room and feeding it back into my own ear. This only happens with "outside" calls. Much more noticeable on the Mitel/Inter-tel digital system phones than with standard analog phones, although even with standard cheap analog phones there is more gain on outside calls than on internal calls. I've tried swapping the 2-line analog line card with a different one, no luck. The POTS lines sounded fine with the old system (Panasonic Hybrid 308) and with a plain old cheap $12 phone plugged into the copper line directly. Frontier has run all their "diagnostics" and finds nothing wrong with their lines.

Try removing the Long Line Programming on the lines and see if the problem is corrected.

Did a bit more investigating last night:

Long line setting is off. Turned it on; no change, the problem occurs regardless of Long Line being on or off.

I moved the 2-line card to the empty analog line card slot in the expansion module. Lines 1&2 are now coming in on Line ports 5&6 but the gain is much more reasonable now, more like what you'd expect it to be. So the problem is not the 2-line card but somewhere on the processor board itself.

I've not started looking at the processor board itself yet, but is there something I should be looking for? Blown caps, trim pots that set the gain on the analog lines?

Thanks!
Doug

Is this a new 3000? Haven't had this happen to me yet. It might be a bad processor board. Have you tried Mitel TS yet or checked the tech message board at MOL?

The 3000 unit is an older Inter-Tel probably late 2007 vintage.. It was purchased by a new business in early 2008 with the intent of installing it and soon upgrading it to support VOIP. The dealer that sold them the system suddenly closed up shop without ever installing it. The small business then called in a second installer who told them that it was a junk system and sold them a Panasonic Hybrid system and installed that. The Mitel 3000 (Inter-Tel Encore CX) just sat in its box for four years until the business owner got tired of employees not being able to figure out the features codes and the many other oddities of their Panasonic system. I get called in to swap out the Panasonic system for the Mitel unit they already own because they really want to add VOIP extensions but then I run into this little issue with CO line gain.

I did call Mitel tech support, since I'm not the original dealer/installer and not a Mitel authorized dealer, no help for me. There is no longer a Mitel dealer within several hours of this town.

Already done the following:
Swapped CO cards with another known good card. NO CHANGE.

Toggled 'LONG LINE' off/on and then back off again. NO CHANGE

Tested CO line with known good POTS phone/line tester. LINE GOOD

Moved CO line card to expansion module. PROBLEM GOES AWAY. This is a solution but not really a fix. Lines show up as 5/6 now instead of 1/2 although the problem is solved for the moment. I would still like it to work correctly though. This is a temporary fix.