Could be noise on the AC or phone line. I had a problem like that this past winter. When the temp went below 30 deg F, I'd get horrendous noise on the phone line - sometimes so much noise that I couldn't get or hear the dial tone.
. They finally traced it to a bad connection in the drop line to my house. Of course that was the last thing they checked... The noise would cut my connections like a knife. You can easily check this by plugging a phone to the modem jack, make a call and just listen without talking for a while.
. There is a parameter that you can add to the init string that will allow your modem to go without the carrier signal a bit longer so it might be able to ride out some short random noise bursts.
. On mine it is: Carrier Loss Hangup Delay (S10=) 1 to 255 where the units are tenths of a second and the default is 14 (1.4 sec.)
.bh.
Hoping again for some :sun:...