Incoming calls drop with static heard

[dcoup]

We have a Panasonic NCP500 PBX with three incoming lines that correspond to three external numbers. This setup was just completed today, porting the three numbers from another carrier for which we used different hardware.

Sometimes when a call comes in, everything is fine. But other times the caller hears static for about one second, and the call drops, regardless of whether anyone answers. It doesn't matter which of the three numbers is called; they all exhibit this behavior.

Our carrier (Comcast) says the problem is in the Panasonic PBX and not in their equipment. What might the problem be?

 

[dcoup]

A little more information about this. If I disconnect the lines for numbers 2 and 3 from the LCOT card, the first number seems to function OK, unless I've just gotten lucky.

 

[obtsystems]

Are they analogy lines on copper or is there a interface box in front of ncp
If you have all 3 lines on the system and put a standard phone on the line does it drop

 

[dcoup]

It's looking like one of the four ports on our LCOT card is bad. I re-cabled the lines so that port was avoided, and things seem to be working better now.

 

[dcoup]

I'm afraid I spoke too soon. It's not a problem with a bad port on the LCOT card. The problem happens regardless of which three ports I use, and it even happens if I have just one of the lines connected.

If I disconnect a cable from the Comcast modem and call the number, it rings with no static problems. If I connect a simple single line telephone to that port, I can call the number and answer the phone without the problem occurring. But as soon as I connect the cable to the PBX, the problem starts happening.

I'll point out that we previously had just a single number with Comcast for testing, and that number worked fine. But now that we have three numbers (ported from another carrier), we're having this problem.