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The Trouble With Faxing Over VoIP and How to Fix It | eFax Corporate

– by eFax Corporate Team

As the world’s leading cloud faxing service for small, medium and large organisations, we receive many enquiries about our online service. And some of the most commonly asked questions are regarding concerns with faxing over VoIP.

Businesses that have made the switch to a VoIP infrastructure often wonder if they will continue to send and receive faxes reliably. And while technically it is possible to fax over VoIP, it’s not without its fair share of problems.

A Word of Caution

VoIP faxing is an undependable method of communication and often falls flat in terms of reliability and efficiency. Your messages may go undelivered, especially with longer documents of more than a couple of pages.

VoIP can cause so many technical issues for professionals that many recommend keeping your traditional telephone line installed, just to ensure you actually receive inbound faxed documents and messages. In these situations, old analogue applications are normally kept in place as a backup in case VoIP goes offline.

Having already paid to have VoIP installed in your office, it would be counter-productive to your office’s finances and productivity to still be relying on traditional methods of communication, as well as paying for expensive line rental and machine maintenance.

This normal practise means that while you’ll always be able to send and receive faxes, you’ll end up paying above the odds for this service, with line rental costing up to £50 per month per telco line.

Is It Possible To Fax Over VoIP?

Back to the main question, is it possible to fax through VoIP? Technically speaking, it is.

But with an increased knowledge of how VoIP networks work, you’re sure to become less confident about its capabilities in regard to your faxing infrastructure. This is especially so if your business deals with important, data-protected faxes or high volume faxing.

VOIP Headset On Computer Keyboard

A Background to VoIP

VoIP, or Voice over Internet Protocol, is a technology that sends voice and other multimedia across data-only networks. It’s the modern replacement and alternative to the familiar circuit-based telephone network.

Rather than sending a conversation across the phone line, it takes any audio delivered in your phone conversation – including all background noise – and converts all of this audio information into a stream of data packets.

Each data packet could be described as a little parcel, which contains all of the vital pieces of information in your voice call, including a destination address and a return address. In that way it is similar to sending a letter through the postal system.

These little parcels are then sent through your Local Area Network (LAN) or Wide Area Network (WAN), and for calls going outside your company, they will pass over the public Internet where they are intermingled with other parcels containing other calls, emails, documents, files, images etc.

When the information is received, the voice parcels are isolated from the rest of the parcels and are then reassembled to resemble the words that were spoken.

Of course, we’re going into great detail here. In reality this process would happen extremely fast, as quickly as a split second. Because of this, parcels are time-sensitive, and if a snippet of a sentence is delayed or arrives out of order, it’s useless and has to be thrown out.

Inconsistences like this can lead to mistakes, mix-ups and slip-ups, the type you hear about in VoIP calls, more so if they’re sent over public internet or travel through a network that often experiences delays and losses due to congestion.

Using VoIP to convert audio is a solution that makes sense. As this option is a great way to save money and keep your company’s office costs to a minimum. VoIP also offers many other benefits that come from moving a multitude of business communications, which may have required a dedicated network, over to a single connection.

Another positive factor associated with VoIP is the fact that it uses reduced bandwidth when making phone calls. As well as converting an analogue voice call into a digital formula, VoIP also greatly compresses that data. Your average phone call, when converted to digital, needs 64 kilobits per second (kbps) of bandwidth.

Using compression tools, we can reduce the number of kilobits in an audio message to as little as 32, 16, or even 8kbps before sending that call through the internet – however this will also mean reduced sound quality.

For larger companies or call-centre businesses, that make hundreds or even thousands of telephone calls each day. VoIP is an obvious solution which can save your business a considerable amount of money.

However, here’s the catch. While numerous types of data can manage and even profit from a certain amount of compression – like audio, video and text files – analogue unfortunately cannot be compressed.

And here is where the issues start.

Fax in a VoIP Infrastructure and Why It Fails to Work

Once of the issues you’ll find with VoIP faxing is that it’s difficult to transmit over an IP network or service.

As mentioned previously, the initial issue with faxing over VoIP is that data cannot be compressed. To transmit a fax, the information must first be digitised for transference over IP as a full 64Kbps data stream.

As a once off occurrence, this shouldn’t cause too many problems, but when your business relies on fax as one its primary means of communication, then this extra step will cost you both financially and in terms of time efficiency.

The extra cost can especially be felt in high number faxing environments, especially during peak hours, when high volume faxing or calling is taking place. The average compressed VoIP call requires about 32kbps, meaning fax consumes double the amount of bandwidth compared to a compressed voice call.

As well as that, there is the IP packet overhead, which increases the necessary bandwidth to 88kbps or to put that into context, that’s a 175% increase in the bandwidth need to make a VoIP call. In addition, fax doesn’t handle data loss and message delay very well, which can cause functionality problems.

One of the advantages of IP is that large files can be compressed or “packetised”, and cut down into smaller, more manageable parcels of information, which are then sent via the internet.

By using this technique, a header which contains the destination or source IP address of each individual parcel is attached – think of it like the “to” and “from” address on an envelope. Other vital information is also included, like the parcel’s place in a broader queue of faxes, e.g. “I’m the third document out of eight that make up this fax”. Details regarding the document’s intended address are also attached, e.g. “Please find attached the IP address of the computer where I’m meant to be delivered”.

All of this means that the IP enables the network to perform its work faster and means that each information parcel will be sent to its intended destination along the clearest route possible. However, this means that snippets of information – such as contact details – can arrive out of order.

More often than not, the process will be somewhat reliable, because the header information aids the system in putting things back together almost instantly upon arrival in the recipient’s inbox. If it happens that pieces of information or data are lost in the process, they can be re-transmitted until the entire message is delivered.

This type of process can work for text documents and emails, where a momentary delay might not be noticed, but this certainly isn’t the case for real-time communications where any delay can prove to be costly.

We’ve all, not doubt, had a mobile phone conversation when the call cuts out and you’ve missed a word or sentence and then have to spend the next minute attempting to fill in the missing pieces of the conversation.

This scenario is something similar to what happens when a piece of data is lost in transmission, however in the case of a phone call, all you have to do is ask the person to repeat what they said. And even if that’s not possible your brain has processes in place to help you fill in the missing words without your brain even realising it. This explains why voice made the transition to VoIP despite its imperfections.

Unfortunately, with regard to faxing, once information is not received it cannot be retrieved and for certain industries this can have disastrous consequences.

For those working within the medical profession, fax is one of the most reliable and secure forms of communication and is used by many private medical practises and the NHS to transmit private patient medical history and sensitive patient information, such as prescriptions.

For these reasons, a high-functioning fax system, which can be relied upon to accurately transmit data safely and securely is vital to their work. In this scenario, all pieces of information are equally important and can’t afford to be lost.

As mentioned previously, faxes can’t be compressed and are not able to handle even the smallest amount of lost data – a 1% reduction, or two-second delay, can result in the fax failing to be delivered. It also doesn’t function when there’s a pause in the sequence, which could cause another delay.

If this happens, your service could interpret all of these separate issues as a bigger problem and as a result abort the whole transmission. Another issue that affects transmissions over VoIP is interoperability problems.

All of the fax machines operating today use a variety of different protocols, with T.30, T.38 and G.711 being the main ones, and transmission speeds like V.14 or V.34. VoIP typically uses G.729 to compress calls and help save bandwidth, which as explained above, cannot be used when a fax comes on the line.

You might be curious to know how fax works then when there are so many different protocols and speeds available. When you send a fax through an analogue network, e.g. your traditional phone system, the two separate machines will open a dialogue with one another and decide on the type and speed of the transmission that they’ll use.

However, when sending a fax over VoIP, any information gaps can cause numerous problems for the recipient’s machine. When a fax travels from a machine that uses one particular protocol and is sent to a machine that uses another, gaps in the analogue tones can occur. This is because the system is trying to decipher the other protocol and convert it. This misinterpretation causes information gaps and synchronisation is lost between the two machines.

To cite one example, VoIP typically uses a G.729 compression and normally has to transfer to G.711 for an uncompressed transferal when a fax is being sent. When it tries to interpret the two different protocols, short pauses in the fax tones can occur, which are likely to lead to the transmission failing. The longer the message, the more likely it is to result in a failed delivery.

However, developments are always on the horizon. T.38 may offer the solution IT professionals are looking for but that day is a long way away. The latest T.38 protocol was created to send faxes over IP, meaning the fax doesn’t initially have to be converted to an audio file.

Technically, two separate T.38 machines are capable of sending and receiving faxes through VoIP, however T.38 is typically connected between two gateways, which must be connected at each side to function properly. Unfortunately, many operators never implemented the protocol, and at this point, many never will.

Even if your telecoms operator supports T.38, a fax which has to cross networks that don’t support T.38, can cause delays, increase costs, and can result in a disconnection. Depending on your machine’s age and model, some T.38s can actually be inconsistent with one another. Failed and delayed communication is normally the result of these technical inconsistences and discrepancies, something no business should have to deal with.

Faxing Over the Information Superhighway

Sometimes it can be hard to fully understand all the technical and unique problems that are created for faxing by using Internet Protocol. One way to look at it, is to think of your standard analogue fax transmission like a presidential motorcade.

Fax is one of the most direct and dedicated communication tools available and offers a straight path from sender to receiver. When being sent across the traditional telephone network, faxes were sent over an enclosed circuit, not used alongside other technologies.

In the motorcade analogy, all other traffic would be blocked and minor roads closed to keep the president’s motorcade free from obstruction and at the same high speed throughout the journey. Also the order of the cars in the motorcade would not change because no unexpected delays would occur.

Professional Women Working On Desktop at Her Modern Desk

In simple terms, all lanes for the motorcade are clear from start to finish, so no delays can take place.

That was the state of the telecommunications network over which fax was designed to operate nearly 40 years ago.

VoIP and other applications based on IP, were created and designed for difficult, complex and shifting traffic conditions. With these protocols, both real time and non-real time information is frantically being sent and received across different lanes.

Some information will even share a lane while being sent, causing some data parcels to arrive in a completely different order to which they were sent. Because the information is sent in such a chaotic way, some pieces of data will inevitably be lost, re-routed or even become stuck in traffic on the motorway.

When traffic jams like this occur, data can easily be lost or received in a completely different order. When delays or rerouting issues happen, the recipient will have to piece the re-arranged information and documents back together again to ensure they make sense.

Fax works best when it has access to its own lane, without any traffic jams or obstructions. However, when issues like this arise, fax will simply stop working, lose information or face unacceptable delays.

Knowing all of the above information and technical issues IT professionals face when faxing over VoIP, we at eFax Corporate will always explain to customers that while you can technically fax over VoIP, it normally creates more issues for a company that it actually solves.

Is There a Solution?

Even though you know all the trouble that faxing over VoIP can cause, it can still be tempting for some companies to still shift their business’s legacy fax infrastructure over to an IP network, and hope for the best.

It’s a well-known fact that IP will create efficiencies as well as save your organisation money. It also centralises your communication technology, meaning less headaches for the IT team.

Hopefully we’ve produced enough evidence to convince you that by faxing over an IP network, your company won’t enjoy the consistent, high-quality, streamlined communication it promises. With that settled, the next question is, “how do I achieve a modern, efficient, cost-effective fax system?”.

Your Four Faxing Options:

1. Leave your traditional fax machine and infrastructure alone and continue to use it as normal. This means that you will continue to pay for a separate and dedicated telephone line.

While this option is a safe one, it still doesn’t solve any of the pre-existing problems with an older fax infrastructure, such as cost and on-going maintenance.

The cost of purchasing paper for your faxes and the expense of repairing and maintaining these old machines is often expensive and tedious, leading to your IT workers spending valuable hours fixing technical issues. Legacy equipment is known for its inefficiencies’ and this problem won’t be going away anytime soon.

2. If you’ve already made the decision and commitment to switch to an IP network and are now facing problems with faxing, there’s always the option of reverting back to the expensive analogue lines. This would be a big step back for your IT department, and in turn would significantly increase your office-costs.

This is because, as well as paying to have VoIP installed, you would now have to pay for dedicated phone lines – or a full network of servers and machines that need their own numbers over digital T1 lines.

3. The third option involves waiting for the standards body to introduce a new protocol that fixes the fax-over-IP issues, like information loss as well as other delay and reliability issues. It’s worth noting that G.711, T.37, T.38 and other protocols are still in operation decades after they were launched. So it might be some time before a permanent and perfect solution is found.

4. The final, easiest, and most cost-effective solution is to move to a cloud fax service. Cloud faxing providers, like eFax Corporate, offer the ideal service when it comes to sending faxes over an IP network – and it won’t require adding anymore technical infrastructure.

Once signed up to eFax, users will be able to send faxes by email, once they know the recipient’s fax number and also add the suffix “”, e.g. [email protected] Once the you’ve added your recipient’s address to the “to” field, you can upload the document, you wish to send as a fax. Once uploaded, type in in the body text and hit send. After the email is sent, eFax cleverly converts your email attachment which is independent of the concealed network technology.

Once converted, the message is transmitted over the network just like a regular fax transmission to its destination. Your communication problem is solved and now employees can easily send and receive faxes from within their email application.

Although the fax is being sent as an email, the recipient will still receive the document in the traditional way, via their fax machine.

eFax Corporate: Cloud Faxing’s Industry Leader

If your business regularly sends confidential documents, then eFax Corporate is one of the best services available when you have to send information securely.

Our cloud service is highly secure and is built on a protected global network, which can upgrade your business’s security and regulatory compliance while enabling your IT department to outsource their infrastructure to an industry leader in cloud faxing.