VoIP Fax Might Work, But There Are More Reliable Options

Although it is possible to send a fax using Voice over Internet Protocol (VoIP), it is not a good idea. VoIP faxing is simply unreliable, and no IT person in the world would recommend that you use VoIP to send a fax.

Faxing is based on analog technology and is incompatible with digital VoIP phone systems that make calls over the Internet.

I’ll explain exactly why, and share specific issues you may encounter when trying to send a VoIP fax. If you need to send a fax without a fax machine or landline, there are simple online fax services that work much better than trying to send a fax using VoIP.

Okay – that’s a quick summary of the key messages. Let’s get into the details.

Why VoIP Faxing Is Struggling

When you make a VoIP call, your voice is broken down and converted into smaller packets of digital data that are transmitted over the network. Each packet contains information that identifies it within the entire signal series. Even if it arrives out of order, each part can be reassembled into the complete original message at the other end.

Fax machines are used to send and receive analog tones over the public switched telephone network, rather than the digital data packets associated with VoIP.

Unlike voice calls, fax data is highly time-sensitive and cannot tolerate packet loss, jitter, or delay.

Essentially, the two technologies rely on different languages ​​- you can’t just connect an analog device (a fax machine) to a digital network (the Internet) and expect them to communicate perfectly.

Connecting an analog fax machine to a digital network requires specialized solutions, such as fax-specific protocols such as T.38. However, it depends on both VoIP provider and receiving devices that support the protocol to ensure compatibility.

See: Learn more about Differences between landline and VoIP communications.

What are the issues with VoIP faxing?

VoIP technology is designed to digitize and transmit voice signals, not fax tones. Fax machines rely on analog tones, which VoIP networks have difficulty handling reliably. This creates some challenges when sending faxes over VoIP.

1. Packet loss and jitter

When the fax machine’s voice is digitized and transmitted over the VoIP network, the data is broken down into packets. These packets may be delayed, arrive out of order, or be lost entirely in transit. Such problems, known as jitter and packet loss, make it difficult for receiving fax machines to reassemble the data correctly.

View:Discover How to permanently fix network jitter.

2. Bandwidth limitation

Fax transmission requires more bandwidth than voice calls due to the larger amount of data involved. During busy periods, insufficient bandwidth may cause transmission failures.

See also: learning How to optimize your network for VoIPfax and other business communications.

3. Agreement interoperability

Fax machines must use the same protocol (usually T.30 or T.38) to communicate effectively. If the sending and receiving devices are misaligned, an error occurs and the transmission may fail. The newer G.711 codec resolves some compatibility issues, but still relies on two machines supporting it.

See: Learn more Use the correct VoIP codec.

4. Network firewall

Firewalls and NAT (Network Address Translation) filtering can block or disrupt VoIP fax transmissions by stripping necessary data from packets. Disabling features like SIP ALG can help, but may put your network at security risk.

See: view Different types of network address translation and when to use each one.

VoIP fax alternative

Use online fax service

When you send a fax using an online service, the platform processes it through its back-end infrastructure and converts it into a format suitable for the recipient’s device – whether it’s an email, a website, or a physical fax machine. This ensures the reliability and compatibility of traditional faxing while eliminating the need for additional hardware on your terminal.

this Best Online Fax Service It has a highly user-friendly interface that can be accessed via a web browser or mobile application. While an Internet connection is required to initiate a fax, recipients using traditional fax machines do not need an Internet connection.

If you only need to send faxes occasionally, a free or pay-per-use online fax service may suit your needs. if you need Fax Check or other sensitive files, please remember The security of a fax depends on the security of its network. It’s always a good idea to use a reputable provider.

For businesses, subscription plans offer enhanced features such as secure file storage, integration with productivity tools, and support for higher capacities.

Using Fax ATA

one FaxATA (Analog phone adapter) is a device that connects a fax machine to a modem or router, converting analog signals into digital data for transmission over a VoIP network.

This is a practical solution for those who want to move communications to digital pipes while continuing to use existing equipment.

The key to a successful setup is to choose a VoIP provider that explicitly supports fax services (not all providers do). With the right provider, a fax ATA can provide reliable performance without the need to switch to online fax services. Fax ATA is an effective and straightforward option for businesses that already have functioning fax machines and want to avoid additional costs or workflow changes.

See also: view Our RingCentral Review Learn more about our favorite VoIP services for faxing.

Maintain separate fax phone lines

A dedicated landline ensures reliable fax transmission, especially for businesses that send or receive large volumes of documents. Unlike some online fax services, you won’t face page limits or need to change your established workflow. This might be a good setup for large-scale fax broadcasts, for example.

However, this approach increases costs. Telecommunications providers typically charge $25 to $40 per month per landline, plus installation fees, which is much more expensive than similar phones Online fax service for small business.

It’s also important to consider that the Federal Communications Commission (FCC) officially removed the requirement for landline support in August 2022. technology, the future availability of these networks is uncertain.

For businesses with high fax volume and a need for reliability, maintaining a landline may still be worth the investment. However, those looking for a long-term solution may explore alternatives such as business phone service With T.38 protocol support and online fax service.