How a Fax Machine Works

Fax machines are relatively old pieces of technology. However, most people have no idea how fax machines actually work.

It’s not rocket science! Today, I’m going to explain how fax machines work and tell you exactly how to use a fax machine.

Users who are trying to use a fax machine without a phone line (and only, for example, an internet connection) should see our page on how to fax from a computer.

History of The Fax Machine

Many people are surprised to learn that fax machines predate the telephone. Before people could transmit their voices down a wire to a receiver, they were able to send images down that wire using faxing.

The world’s first commercial “telefax” service was established in 1865 between Paris and Lyon, France. Despite being over 150 years old, today’s fax machines rely on the same basic technology as those original machines.

Fax machines aren’t as popular as they once were. However, they still play a critical role in many businesses. Until the rise of the internet in the 1990s, fax machines were the best way to quickly send a document or image from one place to another in a short period of time.

How Do Fax Machines Send and Receive Documents?

In both early and modern faxes, the sending and receiving process revolves around the same basic concept:

The machine scans the document
It transfers the image of that document into a signal
That signal is sent down a telephone line to another fax machine
The other machine decodes the signal and reproduces the document

Scanning A Document

As complicated as faxing may seem, it relies on a simple bit of technology. The world’s first fax machines used two codes to indicate whether there was a black or white space on a certain point on the page. Just like binary code indicates whether there is a 0 or 1, fax codes indicate whether there is a white spot or black spot at every point on the page.

The machine scans the document using a photo sensor with a lens and a light. This photo sensor is able to focus on small areas of the page. Early machines were not able to focus as closely as modern machines. An average fax machine focuses on an area of paper approximately 0.01 square inches in size.

Once that area has been scanned and processed, the machine moves horizontally across the paper, scanning as it goes. Once it has reached the end of the line, a drum rotates the photo sensor arm and continues down the entire page.

The first fax machine scans the document and transfers that information into a readable format. All the information on the document or image is broken down into a series of binary codes which indicate either a black or white space at certain points on the page. Then, that coding is sent through the telephone line to arrive at the other end.

Take a look at your computer screen. If you get really close to your computer monitor, you’ll be able to see each individual pixel. Your computer screen is made up of millions of pixels. Each pixel can display a different color. When viewed from further back, these individual pixels collectively make up the words and images on your screen.

Faxes work in a similar way. The black and white squares mean nothing when viewed on their own, but collectively, they form into images and documents.

Modern machines use the same two-tone concept of early machines. However, today’s machines use digital scanning technology in order to create higher resolution images of the documents you’re trying to send.

Modern machines are called digital faxes, while older-style machines are called analog faxes. Analog faxes and digital faxes can easily communicate with one another.

Receiving A Faxed Document

What is your fax machine actually doing once it receives a call?

Your machine is accepting “the handshake”. This handshake is the very first part of receiving a fax. The sending machine initiates the handshake and, once the handshake has been accepted, starts sending a series of beeps to the receiving machine.

These beeps tell the receiving machine that the sending machine is requesting to send a fax. It’s called the handshake because the two machines are essentially introducing themselves to one another before getting down to business.

The main purpose of this handshake is to make sure that the receiving machine is actually a fax machine and not a telephone handset. Once that has been established, the transmission of information can begin.

First, they tell the other machine whether they’re an analog or digital machine. Next, the two machines discuss which compression format they use. Finally, they decide on the format in which to send the fax and begin sending the actual document.

After the message has completely made its way down the telephone line, the receiving machine will send out a confirmation of receipt message. This receipt tells the other machine that the message was successfully received. At this point, the sending machine may print off the confirmation of receipt – depending on the user’s settings.

Meanwhile, on the receiving machine’s end, the fax has processed the information and transmitted that information onto a document using a rotating drum and a type of pen. This pen marks the paper in the same areas as the sent document to effectively reproduce the sent document.

A Basic Step By Step Explanation of A Fax Machine

As mentioned above, faxing isn’t rocket science. It boils down to a few essential points:

Step 1)

Step 2

Step 3)

Step 4)

Step 5)

How To Use Your Fax Machine

Now that you know how fax machines work, it’s time to get your fax machine set up. To set up your fax machine, we’re going to need the following items:

A document
A phone line
A fax machine
A blank piece of paper

The fax number to which you’re trying to send a document

Plug In The Fax Machine

First, plug your fax machine into the electrical outlet and your phone outlet. Many fax machines have two ports: one for the incoming phone line and the other for a third-party telephone. Make sure you’ve inserted the phone line into the correct slot.

To make sure you’ve set everything up correctly, check the phone connection and listen for a dial tone. You should hear the same dial tone sound you would hear when you pick up a phone.

Feed The Fax Machine With Paper

Next, load paper into your machine. Most fax machines have a slot or tray near the back where you can place the paper. If you have a thermal or paper roll fax machine, then you will likely need to open the machine and insert the roll of paper inside.

Configure Fax Machine Settings

Your fax machine should be ready to go. However, you should check three important settings:

Choose whether to receive a fax automatically or manually. “Manual” mode means pressing a button every time you receive a fax. “Automatic” means automatically receiving a fax (most machines are set to “Automatic” by default).
Decide whether or not you want to receive a confirmation page when a page is printed off.
Enter the TSID & CSDI header information. This information appears in the header section of any fax and describes information about the sender – which is you. Make sure this information accurately shows your name or business information (this is particularly important if you’re using a secondhand fax machine where someone has already entered information).

Sending A Fax

Now you can finally send the actual fax. Once you’ve made sure the fax machine is on and plugged into a phone line, simply place the document into the document feeder. Your fax machine should tell you which way to place the fax – look for an icon on the outside of the machine near the document feeder.

Next, dial the number of the receiving fax machine and press the “Send” button. Wait for the fax to complete the transmission process. Once the confirmation of receipt page (or any other information page) is printed off, you can remove the document from the fax machine.

That’s It!

Using a fax machine is easy. The technology has been around for over 150 years and surprisingly little has changed over those years. Businesses continue to use faxing today because it is fast, easy, and secure. However, in an effort to make faxing more convenient, many businesses now use online faxing.