Fax machines might seem a bit old school, but they still hold their ground in many businesses and homes around the world. There might come a time when you need to test a fax line to ensure it’s working properly. But how can you do that with just a phone? Let’s unravel this mystery together.

Understanding fax lines and phone lines

Before we dive into the testing, let’s clarify what fax lines and phone lines are. Essentially, they are the same thing – both are a telecommunication line that transmit audio data.

The main difference is how this data is interpreted by the receiving device. While a phone interprets the data as sounds, a fax machine interprets it as images.

However, it’s important to remember that at the end of some numbers there could be combined fax/phone devices, where a person might pick up the phone. This can be misleading, making you think that they can’t receive faxes. In such cases, you’ll need to inform them you’re going to send a fax and redial.

Recognizing a fax tone

Before you proceed with testing a fax line, it’s important to know what a fax tone sounds like. A fax tone is a distinct sound that a fax machine makes when it’s ready to receive data. It typically starts with a dial tone, followed by a series of high-pitched beeps. This cacophony might seem jarring to the uninitiated, but it’s music to the ears of any fax machine, signaling an attempt to connect with the other side.

The sound is a result of the fax machine converting the image data into audio frequencies, which can then be transmitted over the phone line. These frequencies are modulated to represent the black and white dots that form the images or text on the faxed document.

To help you familiarize yourself with this unique symphony, we’ve included a sound player below with a recording of a typical fax tone. Take a moment to listen to it, so you’ll recognize it when you’re testing a fax line with a phone.

Remember, hearing this sound is a good indicator that the fax line you’re testing is ready and able to receive faxes. If you don’t hear this sound when testing, it could signify an issue with the fax line or machine.

How to test a fax line with a phone: step-by-step

Let’s get down to the nitty-gritty – how can you test a fax line with a phone? It’s easier than you might think!

  • 1. Pick up a landline or cell phone

    Grab your phone and get ready to dial. You don’t need a fax machine to do this. A landline or cell phone is just as good.

  • 2. Dial the fax number

    Dial the number you want to test. Keep in mind what we mentioned about combined fax/phone devices. If a person picks up, simply let them know you intend to send a fax and redial.

  • 3. Listen for specific sounds

    Once the call connects, you should listen carefully. As we mentioned in the “Recognizing a Fax Tone” section above, you’re listening for a series of high-pitched beeps, which is the fax tone. If you hear this, the line is functioning as a fax.

  • 4. Interpreting the results

    If you hear those distinctive sounds, congratulations, the fax line is working fine!

Common problems and troubleshooting

When testing a fax line with a phone, you might encounter some hiccups. Let’s explore a few common issues and their potential solutions.

  1. No dial tone or busy signal: If you don’t hear a dial tone or you’re greeted with a busy signal, there might be a problem with the phone line itself or it’s in use. Try disconnecting any other devices using the line and try again.
  2. No fax tones heard: After dialing the fax number, if you don’t hear the expected fax tones (those high-pitched beeps), it could mean the line is not functioning as a fax. Remember, some devices are combined fax/phone lines. If a person answers, let them know you’ll be sending a fax and redial. If no one answers and you still don’t hear fax tones, there may be a problem with the fax machine or its connection.
  3. Continuous ringing: If the phone just keeps ringing without being answered by a person or a fax machine, it’s possible the number is not currently connected to a fax machine or the machine is turned off. Try reaching out to the owner to confirm.
  4. Poor quality fax tones: If the fax tones you hear are distorted or of poor quality, it could indicate a problem with the line’s quality. This can often result in poor quality faxes or failed transmissions. In this case, it’s worth reaching out to your telecom provider for assistance.

Testing your fax machine’s sending ability

What if you want to test if your fax machine is sending correctly? We have a solution for you. Visit our online fax tester at https://faxbeep.com/. Here, you’ll be provided with a number to which you can send a fax. Once a fax is received at that number, it will get displayed on the fax-tester page. It’s a simple and effective way to confirm your fax machine’s sending ability.


There you have it, a simple way to test a fax line with just a phone. It’s a handy skill to have, especially when dealing with essential fax transmissions. Don’t forget to use our online fax tester when you need to check your fax machine’s sending capability. Happy faxing!