Does anyone know if the broadband talk phone line is stable enough to allow it to be used as a fax line? I know fax is old tech but we still need one for some of our customers and suppliers (all to do with signatures!) and I am not about to rent a dedicated line! I know that in the past, phase jitter meant that fax machines were not too good on voip lines.
I don't think anything's changed. It might work, but it almost certainly won't work reliably.
Are you sure that the incoming calls are coming in on your broadband talk number, and not your PSTN number?
Remember that the phone socket on the hub will receive both lines, if you have set it up that way. The PSTN is simply routed straight through to the socket on an incoming calll. This does not use VOIP.