MODEM losing memory

I have about 30 systems installed in the Eastern US. All are equiped with USR Modem, the most common type.

These have a very good record but lately I have 2 of them gone bizerk on me.

Although I can comunicate with them, I get a "No response from PLC" message when its time to complete the link.

I have programmed these modem through there internal buffers so they do not try anything other than a 9600 / 7E2 protocol.

I got one back from Fl. and checked its buffers. They compare to what I originaly put into them.

It looks and seem OK but I still cannot establish a link in here with 2 normal phone lines. I still have to investigate further.

I only ship my clients another modem and all works OK.

Anyone has an idea on what is happening.

These modem have been unused for 2 years.

Most likely problem if they are in Florida is lightning strikes. Put a good quality surge suppressor on the phone line since this is the likely entry point.

I replaced more modems in Florida than in any other state when I was an OEM.