No, it's a dedicated fax (phone) line, same as the old days. But it routes through a server. Don't ask me to explain it, I'm not much of an IT guy. So it's not a virtual fax, rather it's a fax that appears in an inbox instead of the fax machine actually printing it out.
In our case, our EMR didn't function properly wrt the outgoing faxes, so we had to physically fax papers on the fax machine instead of sending them through the EMR. But we could receive faxes correctly, so we didn't have to pull papers off the machine tray. Just open them up and move them into patient's records.
If something happened to the server, or you disconnected something that wasn't supposed to be disconnected, the fax machine would start printing everything out. It was annoying as hell.