atcomsystems.ca/forum Forums TDM Business Telephone Systems Panasonic Telephones & Systems Panasonic Phones Cutting Out

I have a customer w/ a Panasonic 624 that is dropping co & intercom calls at certain phones. The phone actually powers down and then back up. I have switched the phones to different locations and the problem stayed w/ the extension. I switched extensions and the problem stayed w/ the users location. 90% of the wiring has been replaced in the last 5 years. Have checked it for problems and polarity from cabinet to each phone's line cord and it all checks out. A few phones are in different buildings but some do not have the problem and some do along w/ the phones that are in the main building. Checked all secondary protectors to the outside buildings as well. The phones are a mix between t7030, t7020, & t7730. I mention that b/c the users think the problem happens at the t7730 sets. Any help would be great.

swap out the ksu .does the problem go away ?

Although you say wiring all replaced in the last 5 years, check/replace MDF connections, jacks, and line cords. After all, it looks like you've narrowed it down to building facilities (wiring).

Remember that all it takes is for there to be a short circuit on the data pair of ANY phone to knock eight phones out. When you mentioned phones in other buildings, there's a red flag for sure.

As EV said. Check all data pairs.

I have tested the lines from the line cord from the phone end all the way to the jumper to the ksu. No faults show up at all. I want to replace the ksu however i cant guarantee the customer it will fix the problem. The other buildings are all on the same city block connected w/ arial wiring. We have rebuilt the plant due to various issues over the years. The only connections in it are at the buildings themselves (no splices). Is there possibly a voltage drop I need to look for. A phone shut off recently during a call but the phone came back up and the outside caller was still on the line so not so sure it is the ksu.

since these are going to remote buildings what type of primary protection is in use and what are the distances involved ?

take a couple of the bad extensions and plug them directly into the KSU and test it there

The protectors are solid state and the distances are less the 100', one directly behind the main and one across the street. I would test the phones that way however I can never catch the problem while on site.

I just discovered that the "silver satin" jumpers on a KX-TDA50 phone system were causing problems, specifically when there were two jumpers per extension (one at the KSU and another at the phone). Replacing the jumper with solid wire at the KSU fixed the problem of phones not starting. Perhaps this has something to do with your problem?