atcomsystems.ca/forum Forums TDM Business Telephone Systems Nortel Telephones & Systems NORTEL ICS dropping calls

We have a customer with a Nortel ICS (actually the ICS is shared in a multi tennant environment) using M7310 telephones. All Tenennats generally have about 4 incoming lines each and all have actual line appearance buttons on their phones. They have called saying that when they place callers on hold, the calls drop off and that intermittently when new calls arrive they drop off also. After establishing several test calls, we were actually able to simulate that the calls seem be dropping off when they hit the 2-minute mark of being placed on hold. Also, when the 2-minute mark occurs, if a new call arrives at the same time, they drop off also.

I want to use the term dropping off rather loosly, becasue it appears the calls do not always drop off but rather, the arrows on the display disappear and actually if you press the same line button the calls were on, in most cases, the call is actually still there. It is only the fact that most times, the display goes blank on the phones...all phones. And, if you do not hit the line key within 10 seconds, the caller REALLY drops off as in dead.

When I canvassed the other tennants, all of them said they have been experiencing the same problems for about a month. Funny they never said anything.

We have replaced the phones, and the station cabling. We had the local telephone company check the line voltage and it came back ok.

The lines are loop start and are programmed in the system as such. We reset the timed reminder for hled calls from 120 to 30 seconds and the calls still drop at the two-minute interval.

Do you think there is a problem with the power supply in the Nortel ICS? Any other suggestions?

Have had the same problem on 3 different MICS,all installed within 2 weeks of each other.Replaced trunk cartridges in each system and problem went away.

Thanks for the fast response. Just as a curiosity were the systems you insalled new? The one we are dealing with has been installed for several years.

Any clue as to why all of the trunk cartridges might be bad? The system we are working on must have twenty-two trunks in it.

Yes,systems were new.I think on the cartridges,there was some incompatibility with the newest software.not for sure though.
Is this happening on every line into the KSU?
What is your supervision set to?

you might want to try unplugging the phone system for a minute or two and plugging back in. resetting the system might make the problem go away .

These systems have been working for five years with no problems. The problems cropped up about a month ago. The technician has moved the lines into another KSU, the problems followed, new lines were put into the old ksu, same problems happened with the new lines.

When the problems followed the original lines to the new KSU, we brought in the telephone company to check polarity, move the lines off light span onto copper...They insist all is ok on their end.

The problem is driving us mad. Last night we moved all of the original lines onto a new KSU that was working perfectly fine in another office. Today will be the new test.

Thanks, we tried that first. We have even moved the lines to a different KSU in the same building, the problems followed. So, we assumed the problems were on the lines with the local phone company. We had them test the lines for polarity, We had them move the lines off light span and onto copper. They insist everything is just great on their end. (Where have I heard that before?)

The weird thing is, we even ordered new lines and had them put into the original ksu. Guess what? The problems started happening with the new lines. So, we moved the new lines onto a different ksu. Guess what, the problems existed again.

Last night, we installed a new ksu that had been taken out of another installation because they had upgraded to a new switch. Today will be the new test.

We proved last week that the local phone company had problems on two lines with trip ringing even though they had denied for three weeks they had it. I wonder what else they have that they have not found or admitted to.

Let me know what happens with the new ksu.

i noticed you said provider tested lines for
polarity. how about loop current? that equip might be sensitive to spikes.
martin

The same thing happened. calls dropping, calls dissapearing from hold.