I have seen this. First off, if you have a PRI card, change it. I know you wrote that you monitored the POTS lines, but they may be in addition to the PRI lines.

I have also see a digital card do this. If you have any D12 cards, you may want to replace one with a spare and see if the problem is resolved. If not, move the new card to the next D12 slot and so on.

I find that "when the ground is removed, it works better" interesting. Are you 100% sure you have a valid ground and that ground and the telephone company incoming cable sheath are bonded? If you have voltage potential differences between "grounds," this can create all kinds of weird and phantom problems.

Finally, if you have "fake" dial tone from a cable provider, you may want to examine their grounds (if ANY) and make sure your ground and their ground are bonded.

Rcaman

Americom, Inc.
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