“TEL” on a fax machine or fax modem can mean a number of different things.
It can be:
- The port that is connected to a phone jack by a phone cable.
- The port that is connected to an extension telephone by a phone cable.
- In the context of “FAX/TEL” a switch that changes a fax machine between fax and telephone modes.
A “TEL” port on a fax machine can be somewhat confusing. It is usually 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 just one port for a phone line and it is labeled “TEL,” then the port is to connect the fax to the phone jack.
If there are two ports and one is labeled “TEL” and the other “EXT,” then the “TEL” port is to connect the fax to the phone jack.
If there are two ports and one is labeled “TEL” and the other “LINE,” then the “TEL” port is to connect an extension telephone (an extra phone that can use the same line).