“TEL” on a fax machine or fax modem can be:
- The port connects to a phone jack (sometimes labeled “LINE“).
- The port connects an extension telephone (sometimes labeled “EXT“).
- In the context of “FAX/TEL,” a switch that changes between fax and telephone modes.
A “TEL” port on a fax machine is confusing. It is a port to connect to either the phone jack in the wall or to add an extension telephone so that there can be a fax machine and another telephone on the line.
If there is one port for a phone line labeled “TEL,” it is for the phone line.
If there are two ports, one of which is labeled “TEL”…