What is VoIP?

Emily Dye

Emily Dye

If you’re reading this blog, chances are you’ve been thinking about VoIP.  Maybe someone has mentioned that a VoIP system will save you money; perhaps you’re looking for an easier way to provide remote working options, or you’ve heard about the copper network switch off in 2025.  Whatever your reasons, this blog will talk you through what VoIP is, what you need to use it and give you some things to think about if you’re considering a VoIP solution for your business. 

What is VoIP? 

VoIP stands for Voice Over Internet Protocol.  All it is, is using the internet to route a voice call, instead of a traditional landline.  If you’ve ever placed a call using WhatsApp, Facebook Messenger, or Skype, you’ve used VoIP. 

Most VoIP solutions support standard telephony features and functions.  Because the internet is so much more versatile than landlines, VoIP can support additional features that can increase collaboration and productivity, such as: 

  • Video calls 
  • Instant messaging 
  • Mobility solutions 
  • CRM integration 
  • Analytics 

Now’s probably a good time to get familiar with the most common VoIP terminology: 

IP – Internet Protocol.  Standards for transmitting and receiving data online. 

VoIP – making calls using an internet connection.  Also known as IP telephony or internet calling. 

SIP – Session Initiation Protocol.  The most common solution for delivering voice communication over the internet. 

PSTN – Public Switched Telephony Network.  The nation-wide network of copper wires providing physical paths between phones.  It is this network that VoIP solutions are looking to replace. 

ISDN – Integrated Services Digital Network.  The use of digital transmission for voice and video calls over the PSTN. 

Bandwidth – the capacity to transmit data. Bigger bandwidth means a higher number of concurrent calls.  One concurrent call will require around 100 kbps of bandwidth. 

Latency – the time it takes to transmit data.  Higher latency means a greater delay between the start of transmission and the data being received.  In a voice call, this is the delay from the sound leaving the speaker’s mouth and reaching the listener’s ear.  Latency should be less than 150ms for standard quality voice calls. 

Packet – a small segment of a larger piece of data that is sent over the internet.  In terms of a voice call, instead of transmitting an entire sentence at once, which would take a long time, the sentence is broken up into packets each containing a word or so.   

RTP – Real Time Protocol.  The network standard for delivering packets of voice and video data over the internet.  Used for streaming, voice calls, video calls and other time-sensitive applications.  If the data has been encoded SRTP, or Secure RTP has been used.   

Codec – a piece of code used to compress, encode, and decompress data. 

PBX – Private Branch Exchange.  A general term for a business telephone system.  Traditionally the PBX was the equipment that connected a business to the PSTN/ISDN.  Now, PBXs are usually IP-enabled meaning they will support VoIP. 

Softphone – an application used to make and receive VoIP calls.  These apps can exist on computers, mobiles and tablets and negate the need for a physical handset on a desk. 

How does VoIP work? 

VoIP uses codecs to convert your voice into digital packets.  The codecs compress your voice and encode it into ones and zeros.  These voice packets are sent over the internet using RTP or SRTP and reach their destination almost instantly – they’re only limited by the speed of light.  Once received by the destination, codecs will decompress the packets and convert those ones and zeros back into audio.  The recipient hears your voice as expected. 

What do I need to use VoIP? 

To use VoIP at its most basic level – for a voice call – there aren’t too many requirements: 

  1. An internet connection 
  2. A VoIP provider 
  3. An audio device 

Call quality on VoIP solutions is completely dependent on the quality of your connection.  When evaluating your connectivity things to consider are: 

  • Bandwidth including upload and download speeds.  Higher bandwidth means more concurrent calls.  Or, the busier your phones are, the more bandwidth you’ll need.  Make sure bandwidth is sufficient for your maximum number of concurrent calls (again, allow 100kbps per call) plus all of the other applications your users access.  You may want to consider a separate connection for your VoIP traffic or prioritising this traffic using Quality of Service (QoS). 
  • Bandwidth isn’t the only thing that will affect call quality.  Make sure your connection is stable and the latency is low – less than 150ms is acceptable for a voice call. Providers will often sacrifice latency for bandwidth so it’s a good idea to make sure both values are acceptable. 

Your VoIP provider will connect you to a VoIP service.  There are a couple of different ways they can go about doing this, which we’ll discuss a little later on.  When looking for a VoIP provider, be sure they: 

  • Make your life easier for your business.  Tell them problems you often experience.  They should be able to recommend features to ease these pressures – for example, analytics or CRM integration.  The best service usually provides features beyond just call management, so don’t be afraid to ask what their service can do for you.    

  • Tell you what’s included out of the box. Standard features include auto attendant menus, advanced routing, low-cost international calls, voicemail, call forwarding, monthly minutes bundles etc. 
  • Let you know if you require any additional equipment or services for your chosen solution, for example, a Session Border Controller (SBC). 

Finally, the audio device.  This can be a phone on a desk – most providers include this as an option.  However, more and more businesses are opting for softphones on desktop and mobile devices.  This allows users to be truly agile as softphones connect users to callers wherever there’s an internet connection – whether that’s in the office, at home or in the motorway services.  The expenditure for a mid-range handset on a desk could be better put towards a high-quality headset to be used with a softphone. 

What about SIP?  What’s the difference? 

You may have come across the terms SIP or SIP trunking while researching VoIP, and if so, you may be wondering what the difference is between the two.  VoIP is the broad term to describe any internet-based calling solution; whereas SIP is specific to the type of VoIP solution that has been deployed.  Or put another way, all SIP deployments are VoIP deployments, but not all VoIP solutions use SIP. 

SIP is just one protocol used to deploy VoIP solutions, and it provides unified communications (UC) features, like video, electronic messaging, and file sharing alongside voice.  Because of this, SIP is the most common protocol used to deliver VoIP. 

If your studies have left you trying to compare VoIP vs SIP, this isn’t the best question to be asking.  What is more useful for you to determine, is whether a voice-only VoIP solution best serves your business’s needs, or whether a full UC solution (VoIP enhanced by SIP) is a better fit. 

If you’re not sure the solution you’re looking at is voice-only or SIP, look at the price tag.  A voice-only solution will come in at a significantly lower cost than one that uses SIP. 

How do I go about getting VoIP? 

Your first step should always be reaching out to a trusted VoIP provider like Blackstar.  They’ll be able to help you audit your existing system or PBX.  If it’s doing what you need it to do, just over ISDN lines, there is a reasonable chance you can keep it, but replace the ISDN lines with SIP trunks.  This may involve additional equipment, like a Session Border Controller (SBC) which acts like a firewall between the SIP trunks and your PBX.  You may need some additional licensing on your system too. 

While you’re doing the audit, have a think about what your system does well, what it could improve, whether you’ll keep handsets or go for softphones, how will you support remote working, etc.  Moving to VoIP is more than just a replacement of a PBX, it’s a chance to make improvements and help your users speak to each other more effectively. 

If you need to replace your PBX, or if implementing a VoIP solution is the perfect excuse for a change, you’ll need to decide where your solution will be hosted.  This determines how much ownership and responsibility you have over it.  Depending on your provider, you may have up to three options: 

  • Cloud / hosted.  With this model, everything is handled by the VoIP provider in a data centre.  Nothing is installed on your site, with the possible exception of desk phones.  All technical tasks are handled by the provider.  Hosted solutions are usually billed on an opex model with little to no upfront costs, and predictable monthly bills.  Smaller companies who may not employ and IT person tend to find this option works well for them. 
  • On premise / in house.  All VoIP equipment is located on your premises.  More hardware is involved with this deployment model, meaning more ongoing maintenance.  Upfront costs are generally higher and monthly bills tend to fluctuate.  However, you have more control over all aspects of the system including upgrades and general configuration.  This option tends to work better for larger companies with their own dedicated IT departments. 
  • Hybrid.  This model splits the difference between purely hosted and on prem solutions.  A hybrid model involves some equipment on your site and some in a data centre.  It provides more flexibility and control than a hosted solution but requires fewer in-house skills than on prem.   

If you find any of this confusing, don’t forget your first step was to engage a VoIP provider.  They will be able to advise on the pros and cons of each hosting option, specifically based on your business’s requirements. 

Evaluate your internet connectivity.  Your provider should be able to run some diagnostics on your connection to make sure it’s fit for purpose.  If it isn’t, provisioning a new connection should be your next priority as lead times here will affect when you can go live with VoIP. 

Once the service is in, do some testing.  Pay attention to audio quality:  are there delays?  Do calls drop?  Make sure you place some long test calls as some firewalls have settings that could cut calls off after 11 minutes.  Be sure to test when your network is at its busiest so you know the service can meet your demands all of the time. 

Explore our VoIP phone systems. 

Why should I bother with VoIP? 

A VoIP solution provides loads of benefits to your business including: 

  • Lower costs.  Calls routed over the internet are much cheaper than landline calls.  A lot of providers will include minutes bundles at flat-rate monthly fees, making your bills more predictable.  On top of this, you may not have to pay monthly line rental depending on the solution, and if you do it’s usually 30 – 50% less expensive than ISDN rental. 

  • Accessibility.  Make and receive calls from anywhere using any device that’s connected to the internet.  Should a March 2020 situation recur, it is very straight forward to implement a home-working strategy on a VoIP solution. 
  • Scalability.  With little to no hardware involved, increasing the capacity of a VoIP system is very straightforward.  Licenses or subscriptions for additional users can usually be added on the same day. 
  • Multi-tasking.  VoIP supports not just voice, but a host of collaboration features like video calls, conferencing, file sharing, desktop sharing, instant messaging etc.  

On top of this, VoIP is the future, quite literally.  The ISDN/PSTN network can no longer keep up with the speeds, scalability, and methods of communication needed by businesses today.  From 2023 it will no longer be possible to place new ISDN/PSTN orders, and the entire network will be switched off in December 2025.  If you haven’t thought about moving your system to VoIP, now is the time to start. 

Explore our choice of VoIP phone systems, each with its own unique benefits and features:

To find out how VoIP can benefit your business, to discuss your options regarding the PSTN/ISDN switch off, or to see a demo of any of our VoIP systems, contact us on 0333 123 2 123 or send us an email on [email protected].