‘EXT’ on a fax machine is a port to plug in an extension telephone.
When a phone or answering machine is attached to the EXT port, it will function the same as if it was plugged into the same phone jack as the fax machine.
To use the EXT port:
- Make sure your fax machine is set up and working. It will need to be connected to a landline phone line.
- Using a phone cord, connect the extension landline phone to the EXT port on the fax machine.
- Use the extension phone as you would a regular phone.
An attached extension phone can also be used to check if the phone line is connected and has a dial tone.
Be aware that answering the phone handset when a fax is communicating will stop the transmission.
- Xerox Support Forum – Fax – LINE and EXT – A discussion on the differences between a LINE and EXT port on a Xerox fax machine.
- Epson Support – Connecting a Telephone or Answering Machine – Instructions on how to connect a telephone or answering machine to a fax machine using the EXT port.
- Canon Fax-B840/B820/B822 User’s Guide – page 7 – a Canon fax machine user manual that describes the use of each phone port.
- Epson WF-2750 User’s Guide – page 24 – an Epson fax machine user manual that shows where the “EXT” and “LINE” ports are.
- Xerox Work Center 7120 User Guide – page 24 – A Xerox MFP user manual that shows the location of phone ports on the device. Includes a line for “TEL” as well as 3 different “LINE” ports.