What Is a Fax? Meaning, History, and How Faxing Works Today

What is a fax?

A fax is a scanned image of a document, sent over a phone line to a machine that reproduces it. The word is short for facsimile, which comes from the Latin phrase "fac simile," meaning "make alike."

The sending side scans the page and converts light and dark areas into a signal. The receiving side reads that signal and rebuilds the image. The result is a picture of the page, not editable text.

That detail matters. A fax carries the exact layout, signatures, and stamps of the original. Nothing gets reformatted along the way. This is one reason doctors, courts, and government offices still trust it.

Today a fax does not need a machine at either end. You can send one from an iPhone with Faxend. The office on the other side still receives it on paper or as a PDF. The technology in the middle has changed. The idea has not.

How does a fax machine work?

A fax machine turns a page into black and white dots and sends them as tones down a phone line. The machine on the other end decodes those tones and prints the page.

Here is the sequence in a bit more detail.

1. Dialing and handshake. The sending machine dials the number. The two machines exchange tones to agree on speed and page size. This is the screeching sound you may remember.
2. Scanning. A light bar sweeps across the page. Sensors record each spot as black or white. A standard page becomes a grid of roughly 1,728 dots per line at about 203 dpi.
3. Compression. Long runs of white space are shortened using Modified Huffman coding. This is why a mostly blank page sends faster than a dense form.
4. Transmission. A built-in modem turns the data into tones. Group 3 machines top out at 14,400 bits per second. Super G3 reaches 33,600.
5. Confirmation. After the last page, the receiver sends a confirmation tone. The sender prints or logs a transmission report.

The standards behind this are ITU-T T.4 and T.30. They date to 1980 and are still in use. That is why a 1990s machine can still talk to a modern online fax service.

A short history of the fax

The fax is older than the telephone. Scottish inventor Alexander Bain received the first patent for a facsimile device in 1843, thirty-three years before Bell's telephone patent.

Bain's design used clock pendulums and metal type. It never became a product. Italian physicist Giovanni Caselli improved the idea with his pantelegraph. In 1865 it carried signatures and drawings between Paris and Lyon as a paid commercial service.

Newspapers adopted wire photo services in the 1920s and 1930s. Photographs from Europe reached American front pages within hours. For decades that was the main use.

The office fax era began in 1964 when Xerox introduced the Long Distance Xerography machine. Two years later the Magnafax Telecopier could send a letter-size page in about six minutes over an ordinary phone line.

The real turning point came in 1980 with the Group 3 standard. Japanese manufacturers drove prices down, and by the late 1980s a fax machine sat in almost every office. Sales peaked in the 1990s before email began to take over routine correspondence.

Internet fax got its standard in 1998 when the ITU published T.38 for real-time fax over IP networks. That standard is what lets a phone app and a paper machine exchange pages today. You can read more on the history of the fax on Wikipedia.

Why do people still fax in 2026?

People still fax because many institutions treat a fax as a legally delivered document and distrust email attachments. Healthcare, government, law, and banking are the main holdouts.

Healthcare is the biggest one. The HIPAA Privacy Rule, rooted in the 1996 law, sets strict rules for moving patient records. Fax over a phone line is a point-to-point connection. It was never a target for phishing or mass data breaches in the way email inboxes were. Many clinics built their whole workflow around it and never changed.

Government agencies are a close second. The IRS still lists fax numbers for dozens of forms. Form 2848 for power of attorney and Form SS-4 for an EIN are two common ones. Courts accept faxed filings in many states. Immigration, social security, and unemployment offices often ask for a fax as well.

There is also the legal angle. A fax transmission report is accepted as proof of delivery in many settings. Courts in most US states have accepted faxed signatures for decades. Email read receipts do not carry the same weight.

Finally, faxing is simple. The receiver does not need an account, a login, or a compatible file format. They need a number. For a one-time task like sending a signed lease, that simplicity still wins.

Three ways to fax: machine, T.38, and online fax

There are three practical ways to send a fax today. The oldest is a machine on an analog phone line. The second is a T.38 gateway inside a VoIP phone system. The third, and now the most common for individuals, is an online fax service.

A machine still makes sense if you send stacks of paper every day. For everyone else the phone line fee alone costs more than a year of online faxing.

T.38 is mostly invisible to users. Your VoIP provider handles it. The catch is that not every provider supports it well, and dropped pages are common on poor connections.

Online fax services take a PDF or photo and convert it to the fax image format. A carrier then dials the destination and speaks T.30 to the receiving machine. From the receiver's side it looks like any other fax.

How to send a fax today without a machine

You can send a fax from your phone in about a minute without owning a machine. Upload the document and type the number. Then pay only for the pages you send. No account is required for a single send with Faxend's Basic option.

Pricing is simple. Faxend charges $4.99 one time for 10 pages, with credits good for 30 days. Frequent senders can look at the monthly plans on the pricing page. Every plan is HIPAA-ready with AES-256 encryption.

The iPhone walkthrough with screenshots lives in our guide to sending a fax from an iPhone. If you are choosing between apps, the best fax app for iPhone comparison covers the trade-offs.

How receiving a fax works now

Receiving a fax today usually means a virtual fax number that delivers incoming pages to an app or inbox. The sender dials a normal number and never knows the difference.

A dedicated inbound number is usually a paid feature. On Faxend it comes with the Pro plan at $19.99 per month. Incoming pages arrive as PDFs in your fax history and stay encrypted at rest.

Some people only need to receive once, for example a records request from a former doctor. In that case ask whether the sender can email a PDF instead. If they insist on fax, a short-term number is the way to go. Our guide on how to receive a fax online walks through the options.

Fax vs. email: which one should you use?

Use fax when the recipient requires it or when you need proof of delivery. It is also the safer default for health or tax records going to an office without secure email. Use email for everything else.

Email is faster to write and easier to search. But an attachment sits on mail servers you do not control, and most small offices do not encrypt it. A fax sent through Faxend is encrypted with AES-256 in transit and at rest, then routed to the receiving line.

Fax has real weaknesses too. Image quality is limited to black and white at modest resolution. Long documents cost more per page. And a wrong digit sends your document to a stranger's machine, so check the number twice.

Neither one is going away soon. The realistic answer for most people in 2026 is simple. Use email daily. Keep a fax app on your phone for the few times a year an office demands one. Questions about a specific form or agency? Faxley writes the form-by-form guides on this blog.

Frequently asked questions

What does fax stand for?

Fax is short for facsimile, from the Latin fac simile, meaning make alike. It describes an exact copy of a document sent electronically to another location.

Can I send a fax from my phone without a fax machine?

Faxend turns your iPhone into a fax machine in about a minute. Upload a PDF or snap a photo, enter the number, and pay $4.99 for up to 10 pages with no account or subscription.

Is faxing still used in 2026?

Yes. Healthcare providers, government agencies like the IRS, courts, and banks still rely on fax for signed and confidential documents. Most senders now use an online service rather than a physical machine.

Is fax more secure than email?

A fax over a phone line is a direct connection and is not exposed to inbox phishing, which is why HIPAA-covered offices still accept it. Online services add encryption on top; Faxend uses AES-256 in transit and at rest on every plan.

How long does it take to send a fax?

A single page typically takes 30 to 60 seconds through an online service like Faxend. Older machines on slow lines can take a minute or more per page.

Do I need a fax number to receive a fax?

Yes, the sender needs a number to dial. Online services provide a virtual number that delivers incoming pages to an app or inbox. Faxend includes a dedicated inbound number on its Pro plan.