atcomsystems.ca/forum Forums TDM Business Telephone Systems Nortel Telephones & Systems Compact ICS Intermittent problem receiving and making calls

We have a Nortel CICS system and use the standard 4 port trunk card that connects to the Telco Lines. Recently we have been having problems making calls that would be considered and some time receiving calls. If you unplug the main CICS system, things start working again for awhile. All the display on the phones are working as expected.

Would this be a sign of the trunk card going bad? No configuration changes have been done.

Works best if you post what the symptoms are in detail. So far we know you are just having problems in and out intermittently.

System is around 9 years old.

I will be getting more detailed information later today, but from what I know right now... Currently have 4 lines, with a roll over on the main line. Sometimes when external callers call, they just hear ringing but the actual phone system does not ring. From my experience this usually ends up being a telco problem, with a bad line. They unplug and plugin the CICS things start working again.

Also when dialing some external numbers that have a different prefix, the call does not go through. I am not sure if they get dead air, or a busy signal or what. But, once they reboot the system, it starts working again.

The local telco has been out and claims there is no problems at the DMARC.

I have only see cards go bad in a system like this once, but the unit was struck by lightning (at a different location). I was leaning towards a possible bad trunk card, but didn't know if this is a common thing or not.

Have you made test calls on a butt set from the demarc?

If not that is your next move.

I will do some testing with butt set. According to the telco, when they had a tech out, they were able to make / receive calls from the dmarc. Telco said everything was fine. Then they unplugged the power from the CICS and plugged it back in to get things working again.

I am pretty sure there are two 4 port trunk cards in the system, and I thought about switching them around, and see if the problem follows the card.

Is there logging / debug level that could be turned on and reviewed since the problem is intermittent that may help pinpoint the problem?

I wouldn't give too much credibility to what telco says. If it is happening regularly you should be able to duplicate or eliminate it.

That is step 1 before you swap any cards.

"they just hear ringing but the actual phone system does not ring"

Sounds like the carrier is not sending enough ring voltage (90volts) or the card is starting to fail and cannot detect the voltage well enough.

However this one
"Also when dialing some external numbers that have a different prefix, the call does not go through"

Hook up a Norstar set beside Demarc and listen with your butt set to see if DTMF is going out on those bad prefixes when you dial them.


-measure inbound voltage
-listen for DTMF
Then swap out the card

Is this on all 4 lines or just some lines?

Is there a certain voltage range when the phone is not ringing that it should be around as well?


I was able to look at the unit yesterday and talk with the users of system... Unfortunately they were not having a problems at the time, so I couldn't check anything with a butt set.

They mentioned that when calling out, the problem was they heard the dial tone through the phone (all lines), but when the buttons on the phone were pressed, the dial tone was still there, like it didn't get a signal when they pressed the buttons.