So I purchased an FVC-100 in November to " upgrade" my phone system. We have 1 line (out of 8 analog) that has NEVER worked. For some reason between going from Build 0005 and Build 0007, two or three times a day, we loose all external lines and have to reboot the PBX. I have one line that has constant echo on it and a conference phone that has such severe chop when used that we had to stop using it. So you think ok, Hardware problem... well this is on our " new unit" that we got last month after our old unit had two dead analog ports.
I' ve tested all of our analog lines, they are fine. I highly doubt it' s a telco problem.