atcomsystems.ca/forum Forums TDM Business Telephone Systems Vodavi Telephones & Systems Vodavi STS CO lines disappear

My customer has an STS (3500)with 1.04 firmware. I replaced the cmos battery about a year ago and they have been running without any problems until 3 weeks ago. They have a recurring problem where they cannot get an outside line. Pressing a co line button gives them a fast busy. The phone lines have been checked. If they unplug the power to the KSU and plug it back in, the phone lines may work for the rest of the day. There are 4 lines on the system. When I checked the system, I could not get a line by pressing a button, dialing 9, or by dialing 801. Pressing a line button on a phone does not even try to get a line. It simply gives a fast busy like an unprogrammed button does. I can call to other phones on the system by dialing the station number or pressing a dss on the phone. If I simply press the reset button on the KSU I am again able to access outside lines. Note that this problem also prevents the customer from receiving incoming calls as well. This is the first time I've ever seen this on an STS. Any ideas?

It is old. That is the main problem. Could be a bad co port card, could be a bad cid module on the card itself (or on the backplane). Could be a power supply is going south.

If you check the button programming using off-hook, [Speed]+[7]+[#]+[2], is the programming still correct? If so, I would agree with Derrick. If not, then the MPB might be failing. Either way, the KSU will likely need to be replaced.

Couldn't hurt to reinit it.