It could be line voltage on your customers lines and we all know how the phone company hates when you call them on it.
Most if not all modem/fax/dss modem or tivo modem problems we have had in the past were due to loop curent. Too high in one case too low.
Also put your fax on another line and try it.
[Link: sandman.com][Link: sandman.com]http://www.automatedhomes.tv
