How to install a fax line

Last Update: August 9th, 2021

Many people choose to install a dedicated fax line for their fax machine. It adds the ability for a fax to have its own dedicated fax number that isn’t interrupted by regular phone activity.

Here is how it’s done.

Step 1 – do you need a fax line?

There are other options to a dedicated fax line such as:

A dedicated fax line can be used with:

Step 2 – what you’ll need

A fax line is simply an extra phone line. It can run parallel to existing phone lines, or it can be reserved to a specific phone jack.

There are two sets of wiring involved in a fax line:

  1. The telephone company’s connection to the phone box for the building.
  2. Wiring within the building that connects fax machine directly to the phone box.

Step 3 – run wiring inside the building (if not wired internally already)

There are two ways to wire a fax line internally:

Option 1 – Configure an existing line to be fax only. This method would change a phone line into a fax line.

The benefit of this method is that it is usually very cheap to do – it simply changes a specific phone jack to be a fax line instead of a landline.

Usually, this change is as simple as moving the connection of a phone line at the phone box. The telephone company may be able to make the change while installing an additional line.

Sometimes this method won’t work if the line splits into two somewhere between the phone box and the phone jack (all lines using that specific connection to the phone box would become the fax line).

Option 2 – Run a brand new line from the phone box to the destination phone jack. This method would add an additional line within the building. It can put a phone line and fax line right next to each other.

Wiring inside of the building is the largest unpredictable cost when adding a fax line. A physical telephone line has to be run from the phone box to the location of the phone jack. Each building is different. Typical costs include running the line, fixing drywall (and sometimes repainting the wall), fixing ductwork, and the cost of the phone jacks.

Sometimes this is a simple operation (for example the phone jack is close to the phone box, or there is a nearby air duct that can carry the wire most of the way, or the line can be run along a baseboard or under carpet). Other times this is an expensive option (the phone jack location is far away, or in a difficult to reach location).

Step 4 – connect the additional fax line to the building

Contact your phone company to have an extra phone line added to the building.

In most situations, the phone company only needs to send a technician to the building to install the fax line.

In some cases, there may be a need (and cost) for running the extra line from the phone company’s phone lines on the street to the building.

Step 5 – connect your fax machine and enjoy

Set up your fax machine or computer with fax software and connect it to the fax line. Test the fax, and you should be ready to fax.

Sources and more resources

HomePhoneWiring.com – Adding a Jack to an Existing Phone Line and Adding a Second Line to Your Existing Phone Jacks – Instructions on wiring phone lines through a house. Overall a very good resource for phone line installation and maintenance.

This Old House – Adding a phone line and Adding a second phone line – Instructions on adding and running phone/fax line throughout a house. These ideas could also be applied to an office or industrial building.

DoItYourself – Telephone Wiring: How to Add an Extra Extension and Check for Problems and How to Hook Up a Second Phone Line – Instructions on running a phone/fax line throughout a house. This “how to” could apply to an office or industrial building.

FamilyHomeHandyman.com – Fishing electrical wire through walls – instructions on how to “fish” a wire through the walls of a building.

The Trench – How to fish wires through a wall or ceiling – Instructions on how to fish a wire through the walls or ceilings of a building.

Digital Home Forum – Running low voltage wiring to exterior walls – A forum discussion on how to run low voltage (for example telephone) wire to exterior walls.

YouTube – 7777jayhawk – New telephone line wire run from outside service box to inside, repair landline, THE TRUTH, CAT3 – A demonstration video on running a line from the phone box, as well as fixing an existing landline. It’s a longer video at 10 minutes, however, it does explain most of the workings of a home’s phone system and how it connects to phone jacks.

YouTube – Expert Village – How to Install a Phone Jack : Tapping Into an Existing Phone Line for New Phone Jack – a demonstration video on how to install an extra phone jack onto an existing phone line. This method simply adds a second phone jack to an existing line and does not place a new “line” to the phone line.