More and more businesses make their calls over the internet. With the UK's analogue landline network due to be switched off by the end of January 2027, VoIP is becoming the normal way to run a business phone system, whether that means desk phones, a softphone app on a laptop or calls on a mobile.
VoIP can sound excellent, but only if the broadband and network behind it are set up well. This guide explains what matters for clear calls and how to get it right.
What is VoIP?
VoIP stands for Voice over Internet Protocol. Instead of travelling over a copper phone line, your voice is turned into small packets of data and sent over your internet connection, usually to a hosted phone system in the cloud that connects your calls to the rest of the phone network.
Because it uses your broadband, VoIP brings flexibility: phones can move with you, staff can take calls at home, and features such as call queues, voicemail to email and call recording are built in. It also means call quality depends on your connection.
If you are still using traditional phone lines, our guide to the UK landline switch off for businesses explains what is changing.
What your broadband needs for clear VoIP calls
Stability matters more than headline speed
A voice call uses only a small amount of bandwidth compared with streaming video or downloading files. Most call quality problems are not caused by a slow connection, but by an unsteady or overloaded one. Delay, gaps and variation in how packets arrive are what make calls sound choppy.
Upload speed
A call sends your voice out as well as bringing the other person's in. If your upload is small and someone starts a large cloud backup or sends a big file, calls can suffer. Full fibre usually offers far more upload than older copper based broadband, and a leased line gives matching speeds in both directions. Our guide to symmetric and asymmetric broadband explains why that helps.
Latency
Latency is the time it takes for data to travel to its destination and back, often shown as ping in a speed test. Low, steady latency keeps conversations natural. High latency causes the awkward pauses where people talk over each other.
Jitter
Jitter is variation in latency. If packets arrive unevenly, the phone has to smooth them out, and when it cannot, you hear clipped words or robotic sounding audio.
Packet loss
Packet loss is when some data never arrives. Even a little can cause gaps in speech. It is often a sign of a WiFi problem, a faulty cable or an overloaded connection.
How many calls can my broadband handle?
That depends on the codec your phone system uses, how many calls happen at once and what else is using the connection. Rather than working from a rule of thumb, look at your busiest time: how many people are on calls, and what else is happening, such as video meetings, cloud backups or large uploads. Our guide to how much broadband speed a business needs can help, and your phone provider can tell you what each call uses on their system.
Set up your network for calls
Wire your desk phones
Desk phones should be plugged into the network with a cable. Many businesses use a network switch that supplies power over the same cable, known as PoE, so phones do not need separate power adapters. Softphones on laptops work over WiFi, but a wired connection is steadier for people who spend all day on calls.
Strong WiFi for mobiles and softphones
If staff take calls on laptops or mobile apps while moving around, WiFi coverage needs to be good throughout the building. Weak spots cause dropped calls as people walk between rooms. Our guide to business WiFi covers how to plan coverage, and our WiFi page explains the options we offer.
Prioritise voice traffic
Many business routers support quality of service, or QoS, which gives voice traffic priority over downloads and backups. On a busy connection, this can make a real difference. It works best when set up to match your phone system.
Check SIP ALG and firewall settings
Some routers include a feature called SIP ALG that tries to help VoIP traffic through the firewall but can end up interfering with it, causing one way audio or dropped calls. Many phone providers recommend turning it off. Check with yours before changing anything, as requirements vary.
Plan for outages and power cuts
If your broadband goes down, so do your VoIP desk phones. There are simple ways to protect yourself:
- Call diverts. Many hosted phone systems can send calls to mobiles automatically if your office phones go offline.
- Backup broadband. A mobile or second fixed connection with failover keeps phones working. See our guide to backup broadband and failover.
- Power. Phones, routers and switches need power. A small uninterruptible power supply keeps them going through short power cuts.
Emergency calls
You can still call 999 or 112 on a VoIP phone, but make sure your phone provider has the correct address for each location where phones are used, so emergency services know where to go. If anyone relies on a phone line for a telecare alarm or similar device, check with the device supplier that it will work.
Troubleshooting poor call quality
- Note when problems happen. If they are worse at certain times, something else on the network may be competing with calls.
- Test a call on a wired phone. If it is clear, the issue is probably WiFi.
- Run a speed test and look at ping and jitter as well as speed. Our guide on how to test broadband speed explains what the results mean.
- Check for large uploads or backups running during the working day.
- Speak to your phone provider and broadband provider together if the problem continues.
Business phones from Virtual Voice
You can add one business phone line to your Cyber Fibre broadband when you order, and keep your number. For several lines, VoIP handsets and team calling plans, our sister company Virtual Voice Office, part of Virtual Voice, can help. Because we are part of the same group, we can help make sure your connection and phone system work well together.
Get a connection that is ready for calls
Check your address to see business full fibre packages, request a leased line quote if you handle a high volume of calls, or contact our team in Sunderland to talk through your phone and broadband setup.