For a long time I've been using a HylaFax server and an old external 56k serial port modem.
It has worked great on our POTS lines.
Recently we just upgraded our location and it now has an AT&T Fiber connection, and the telephone lines are all provided over the Fiber line.
Now, the old modem apparently isn't picking up when it gets an incoming call. I'm not sure why, but it's definitely some incompatibility between the new lines and the modem because I've tested the following:
- Old modem and Hylafax server still work fine on old POTS lines
- Old modem won't pick up incoming fax call on new fiber lines
- Standalone fax machine DOES pick up incoming fax call on new fiber lines
Why doesn't the old modem detect or answer the incoming call?
How can I get my old modem to work with the new lines?
This is a common problem with old phone devices (your modem) and newer telephone company hardware: the type of hardware provided by the telephone company doesn't provide enough ringing voltage for the modem to recognize an incoming call.
But first things first, if you haven't tried the working fax machine on that same phone line that the modem is connected to, do that. There might be a problem with that specific port.
If that works, you might try reversing the tip/ring wires. It's not out of the question that your modem could be sensitive to that, especially if the modem or the telephone company equipment (wrongly) grounds one of those wires.
Next, call the telephone company and ask them about it. They may have a solution for you. If not, you could buy a ring booster.
If you need a new modem, I doubt any manufacturer specifically lists "works with impotent telephone company equipment that doesn't generate high enough ring voltage". But there probably is a Hylafax community out there somewhere that does have a specific model recommendation.