We were hired by a friendly competitor to help him figure out why a Panasonic KX-TDA50G keeps dropping calls in progress. It also randomly drops calls that are on hold. There are many more details to this story, however:

1. The original system there was a KX-TAW848 with 7731 phones that began doing the same thing, so the guy replaced the KSU with another 848, but the problem persisted.

2. He then replaced the 848 with the 50G and the problem still remained.

3. Upon our advice, he installed Sandman's loop current regulators on the CO lines but they had no effect.

4. We have never been able to re-create the problem while on site, but several of the staff there have told us that they will be in the middle of a call, they will hear a click and then the system returns a reorder tone. This leads me to believe that they system is doing exactly what it is supposed to do; responding to a momentary open loop on the line and releasing it.

5. Verizon has supposedly changed the cable pairs to the building, in fact they were there during one of the visits that we made.

6. There is no noise or static whatsoever on any of the lines. I am starting to lean toward the fault being on one specific line, maybe the second or third one since the problem is so sporadic. I really don't think that there is anything wrong with the system or the wiring.

7. The serving central office is a 5ESS (ARTNVAARDSO). I would like to demand that Verizon change out the office equipment for this customer, but in order to get them to do so, we have to exhaust all other avenues.

Any ideas? I'm up against a brick wall on this one.

Ed Vaughn, MBSWWYPBX