VoIP Problems? 10 Common Issues and How to Fix Them (Before You Throw the Phone Out)

Last updated: March 2026

VoIP is brilliant when it works. Crystal-clear calls. Professional features. Fraction of the cost of a traditional phone system. Easy to scale. Works from anywhere.

When it does not work? It is infuriating.

Robotic voices. Calls that cut out mid-sentence. Echo that makes you sound like you are talking in a cave. One-way audio where you can hear them but they cannot hear you. Your caller ID showing the wrong number. Calls going straight to voicemail when your phone is sitting right there, ringing silently.

You did not switch to VoIP for this. You switched because it was supposed to be better.

Here is the good news: almost every VoIP problem has a fix. And here is the really good news: about 80% of VoIP problems are not actually VoIP problems at all. They are broadband problems. Fix the broadband and the VoIP fixes itself.

At Compare The Networks, we set up and support VoIP systems and virtual landlines for hundreds of UK businesses. We have seen every problem on this list hundreds of times. This guide covers the 10 most common VoIP issues, what causes each one, and how to fix them, in plain English, step by step.

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The Dirty Secret: 80% of VoIP Problems Are Actually Broadband Problems

Before we get into the individual issues, you need to understand this: your VoIP system is only as good as your internet connection.

VoIP converts your voice into data packets and sends them across your broadband connection. If your broadband is slow, congested, unstable, or has high latency, those packets arrive late, out of order, or not at all. The result? Choppy audio. Dropped calls. Delays. Everything you are experiencing.

Think of it like a motorway. Your voice is a car trying to get from A to B. If the motorway is clear, the journey is smooth and fast. If the motorway is congested with lorries (other internet traffic, downloads, streaming, backups, cloud apps), your car gets stuck in traffic. Bits of your voice arrive late. Some do not arrive at all.

What good broadband for VoIP looks like:

The critical number is upload speed. Most broadband packages advertise download speed because that is what consumers care about (streaming, browsing). But VoIP sends data upstream, your voice goes FROM your office TO the internet. If your upload speed is poor, your voice quality will be poor, even if your download speed is fine.

Standard FTTC broadband (the most common type in UK businesses) typically offers 80Mbps download but only 20Mbps upload. That is workable for VoIP, but only if you are not sharing that upload bandwidth with other demanding tasks.

Many older packages, ADSL connections, or cheaper fibre packages offer only 2-5Mbps upload. That is not enough for reliable VoIP, especially with multiple simultaneous calls.

Our recommendation: Sky Business Broadband SOGEA 80/20 at £35+VAT. The 80Mbps download handles everything your office needs. The 20Mbps upload is specifically why we recommend it for VoIP, it is enough for 15-20 simultaneous calls with bandwidth to spare. And at £35+VAT, it is competitively priced against consumer-grade connections that would let your calls down. Contact us for availability at your location.

How to test your broadband for VoIP suitability:

1. Go to speedtest.net from a device connected to your office network.
2. Run the test 3 times: morning, midday, and afternoon. VoIP problems often occur at peak times when your broadband is busiest.
3. Note the upload speed, download speed, and ping (latency).
4. If upload is under 5Mbps or ping is over 50ms at any time, your broadband is likely causing your VoIP problems.

Now let us fix the specific issues.

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Problem 1: Choppy or Robotic Voice

What it sounds like: The other person's voice breaks up into fragments. Words are garbled. It sounds like a robot is talking. Sometimes words are missing entirely.

What causes it:

• Insufficient bandwidth. Your broadband does not have enough upload speed, or other devices on your network are consuming the bandwidth VoIP needs.
• Network congestion. Too many devices competing for the same connection. Someone is downloading a large file, streaming video, or running a cloud backup while you are on a call.
• Jitter. Data packets are arriving at irregular intervals. Your VoIP system can handle some variation, but beyond a certain point, it cannot reassemble the audio correctly.
• WiFi interference. If your VoIP phone or softphone is connected via WiFi, wireless interference can cause packet loss.

How to fix it:

1. Test your broadband. Run a speed test during the time when calls are worst. If upload speed is under 5Mbps, you need better broadband.
2. Use a wired connection. If your VoIP phone is connected via WiFi, switch to an Ethernet cable. Wired connections are dramatically more stable for voice.
3. Enable QoS (Quality of Service) on your router. This tells your router to prioritise voice traffic over everything else. See the router settings section below for how to do this.
4. Identify bandwidth hogs. Is someone downloading large files during calls? Is there a cloud backup running at midday? Schedule heavy downloads for outside business hours.
5. Upgrade your broadband. If your connection is fundamentally too slow or unreliable, no amount of tweaking will fix it. Contact us about Sky Business Broadband SOGEA 80/20 at £35+VAT, it is purpose-built for this.

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Problem 2: Calls Dropping

What it sounds like: You are mid-conversation and the call simply ends. No warning. No error message. Just silence. When you try to call back, it might work fine, or it might drop again.

What causes it:

• Broadband dropouts. Even a 2-second internet outage will kill a VoIP call. Your broadband might be "up" 99% of the time, but that 1% is enough to drop calls regularly.
• Router overload. Consumer-grade routers can struggle when handling VoIP alongside heavy internet traffic. They run out of memory or processing power and drop connections.
• SIP registration timeout. Your VoIP phone periodically "checks in" with the VoIP server to confirm it is online. If this check-in fails (due to a brief internet interruption), the phone gets deregistered and calls drop.
• ISP throttling. Some broadband providers throttle certain types of traffic during peak hours. If they are throttling VoIP traffic (which appears as UDP on ports 5060/5061), your calls will drop.

How to fix it:

1. Check your broadband stability. Ping your router continuously for an hour (open Command Prompt/Terminal and type ping 8.8.8.8 -t). If you see "Request timed out" messages, your broadband is dropping intermittently.
2. Restart your router. Seriously. If your router has been running for months without a restart, it may have accumulated errors. Power it off for 30 seconds, then back on.
3. Replace your router. If your router is more than 3 years old, or if it is the free one your ISP provided, consider upgrading to a business-grade router. A decent one costs £80-£150 and makes a significant difference for VoIP.
4. Check for broadband line issues. If dropouts are frequent, contact your ISP and ask them to run a line test. There may be a fault on the line that is causing intermittent disconnections.
5. Switch ISP. If your current broadband is fundamentally unstable, changing ISP may be the most effective solution. Not all connections are equal, even at the same address, different ISPs use different equipment and have different levels of reliability.

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Problem 3: Echo on Calls

What it sounds like: You hear your own voice repeated back to you with a slight delay. Or the other person hears their own voice echoed back. It is disorienting and makes conversation nearly impossible.

What causes it:

• Acoustic echo. Your microphone is picking up audio from your speaker. This is common with speakerphones, laptop microphones, and headsets with poor noise isolation.
• Network echo. Caused by impedance mismatches at the point where your VoIP call connects to the traditional phone network (if the other person is on a landline or mobile).
• Double connection. A rare but frustrating issue where the call is being routed through two audio paths simultaneously, creating a feedback loop.
• High latency. When there is a significant delay on the call (more than 150ms), echo becomes noticeable even at low levels. Normally, echo suppression in VoIP devices handles small amounts of echo, but it cannot cope when latency is high.

How to fix it:

1. Use a headset instead of speakerphone. A proper headset with a close-talking microphone eliminates acoustic echo completely. A decent USB headset costs £25-£50 and is the single best investment for VoIP call quality.
2. Reduce speaker volume. If you must use a speakerphone, lower the volume. The louder the speaker, the more audio the microphone picks up, the worse the echo.
3. Check your latency. If ping to your VoIP server is above 150ms, echo becomes more noticeable. High latency is usually a broadband issue, see Problem 6.
4. Enable echo cancellation. Most VoIP phones and softphones have echo cancellation settings. Check your phone's admin interface or softphone settings and make sure it is turned on.
5. Update firmware. VoIP phone manufacturers regularly update their firmware with improved echo cancellation. Check for updates on your phone model's support page.

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Problem 4: Cannot Make Calls But Internet Works

What it sounds like: Your internet is working fine, you can browse, email, everything. But when you try to make a VoIP call, nothing happens. No dial tone. No ringing. Just silence or an error message.

What causes it:

• SIP registration failure. Your phone is not registered with the VoIP server. This usually means the phone cannot reach the server, even though your general internet works.
• Firewall blocking SIP traffic. Your router's firewall or a network firewall is blocking the ports that VoIP uses (typically port 5060 for SIP and ports 10000-20000 for RTP).
• Incorrect credentials. The SIP username, password, or server address in your phone's configuration is wrong. This can happen after a provider change, a phone reset, or a firmware update that cleared settings.
• VoIP provider outage. Your VoIP provider's server may be down. This is rare with reputable providers but does happen.

How to fix it:

1. Check your phone's registration status. On most VoIP phones, there is an indicator (usually on the screen or a status LED) showing whether it is registered with the server. If it shows "unregistered" or "failed," the problem is clear.
2. Restart the phone. Unplug it for 10 seconds, plug it back in, and wait 2 minutes for it to re-register. This fixes the problem about 40% of the time.
3. Check your firewall settings. Make sure SIP (port 5060/5061) and RTP (ports 10000-20000, or whatever range your provider uses) are not being blocked. See the router settings section below.
4. Verify credentials. Log into your phone's web interface and check that the SIP credentials (server, username, password) match what your VoIP provider has given you.
5. Contact your VoIP provider. If none of the above works, it may be a server-side issue. Ask them to check your account registration and server status.

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Problem 5: Callers Cannot Hear You (But You Can Hear Them)

What it sounds like: You pick up the call. You can hear the other person clearly. You speak. They hear nothing. They say "hello? hello?" and you are shouting into a phone that is transmitting silence.

What causes it:

• Microphone failure. The simplest explanation. Your headset or handset microphone has failed or is not selected as the audio input.
• NAT traversal problem. This is the most common technical cause. Your router's NAT (Network Address Translation) is not correctly handling the outbound audio stream. Your voice packets are being sent but are not reaching the other end.
• One-way firewall block. Your firewall is allowing incoming audio (so you can hear them) but blocking outgoing audio packets.
• SIP ALG interference. Your router's SIP ALG (Application Layer Gateway) feature is mangling the audio setup, causing outgoing audio to be misdirected. This is the most common single cause of one-way audio.

How to fix it:

1. Check your microphone. Test it on another application (Teams, Zoom, or a voice recorder). If it does not work there either, it is a hardware issue. Replace the headset or check the handset connection.
2. Turn off SIP ALG on your router. This is so important it gets its own section below. SIP ALG is responsible for roughly 50% of all VoIP issues. Turn it off.
3. Enable STUN or TURN on your VoIP phone. These are NAT traversal protocols that help your phone send audio through your router correctly. Your VoIP provider can give you the STUN server address to configure.
4. Check firewall rules. Make sure outbound UDP traffic on your RTP port range (typically 10000-20000) is allowed.
5. Put your VoIP phone in the router's DMZ temporarily. This bypasses the firewall entirely for that device. If it fixes the problem, you know the firewall is the issue, then you can create specific rules rather than leaving it in the DMZ permanently.

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Problem 6: Delayed or Laggy Audio

What it sounds like: There is a noticeable delay between when you speak and when the other person hears you. Conversations become awkward because you talk over each other. It feels like a satellite phone call from the 1990s.

What causes it:

• High latency on your broadband. The time it takes for data to travel from your office to your VoIP server and on to the other person is too long. For comfortable conversation, total latency needs to be under 150ms. Over 300ms and conversation becomes very difficult.
• Geographic distance to VoIP server. If your VoIP provider's server is in another country, latency increases. UK businesses should use VoIP providers with UK-based servers.
• Network congestion. Your broadband is overloaded, causing packets to queue up before being sent. This adds latency on top of the normal connection delay.
• WiFi latency. WiFi adds 5-20ms of latency compared to wired Ethernet. If your broadband latency is already borderline, WiFi pushes it over the threshold.

How to fix it:

1. Measure your latency. Open Command Prompt (Windows) or Terminal (Mac) and type ping [your-voip-server-address]. Your VoIP provider can tell you the server address. If ping is consistently above 80ms, you have a latency problem.
2. Use wired Ethernet. Switch from WiFi to a wired connection. This reduces latency and eliminates WiFi-related jitter.
3. Reduce network congestion. Enable QoS on your router to prioritise VoIP traffic. Schedule large downloads and backups for outside business hours.
4. Check for ISP congestion. Run speed tests at different times of day. If latency spikes during business hours but is fine at night, your ISP's network is congested.
5. Switch to a closer VoIP server. If your provider has multiple server locations, ask to be moved to the nearest UK server. Reducing geographic distance directly reduces latency.
6. Upgrade your broadband. If the underlying connection has high latency (common with ADSL and some older FTTC connections), no amount of QoS will fix it. You need a faster, lower-latency connection.

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Problem 7: One-Way Audio

What it sounds like: Similar to Problem 5, but it can go either way, sometimes you can hear them but they cannot hear you. Sometimes they can hear you but you cannot hear them. Sometimes it works in both directions for the first 10 seconds and then goes one-way.

What causes it:

• Firewall blocking RTP ports. RTP (Real-time Transport Protocol) carries the actual audio. If your firewall blocks these ports in either direction, you get one-way audio.
• Symmetric NAT. Some routers (especially those provided by ISPs) use a restrictive type of NAT called symmetric NAT, which breaks VoIP audio streams.
• SIP ALG (again). This feature is so harmful to VoIP that it deserves to be mentioned in every section. SIP ALG modifies the SIP packets as they pass through your router, and it frequently gets it wrong, resulting in one-way audio.
• Double NAT. If you have two routers in series (for example, your ISP's router plus your own router), you have double NAT. This confuses VoIP audio routing and causes one-way audio intermittently.

How to fix it:

1. Turn off SIP ALG. (See section below.)
2. Open RTP ports on your firewall. Your VoIP provider will specify the exact port range, but it is typically UDP ports 10000-20000. Create a firewall rule to allow both inbound and outbound traffic on these ports.
3. Fix double NAT. If you have two routers, either: (a) put the ISP router into bridge/modem mode so only your router handles NAT, or (b) connect your VoIP phone to the ISP router directly rather than going through both.
4. Enable STUN/TURN. Configure your VoIP phone with your provider's STUN server. This helps with NAT traversal and resolves many one-way audio issues.
5. Replace restrictive router. If your ISP-provided router uses symmetric NAT and you cannot change it, use a different router. A business-grade router with VoIP-friendly NAT handling costs £80-£150 and eliminates this category of problems entirely.

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Problem 8: Caller ID Showing Wrong Number

What it sounds like: When you call someone, your number shows up incorrectly on their phone. It might show a different number, "Unknown," "Withheld," or a number from a different area code.

What causes it:

• CLI (Calling Line Identification) misconfiguration. Your VoIP provider or phone system is not correctly presenting your outbound number.
• Number not verified with the provider. OFCOM and telecoms regulations require that CLI numbers be verified. If your VoIP provider has not verified your outbound number, they may block or replace it.
• Multiple numbers, wrong one selected. If you have several numbers (a main number, a direct dial, a virtual landline), your phone system may be presenting the wrong one for outbound calls.
• SIP trunk configuration. If you are using a SIP trunk for your phone system, the outbound CLI needs to be correctly set in the trunk configuration.

How to fix it:

1. Check your outbound CLI setting. In your VoIP phone or phone system admin panel, check which number is set as the outbound caller ID. Make sure it is the number you want displayed.
2. Verify the number with your provider. Contact your VoIP provider and ask them to confirm that your outbound number is verified and correctly configured on their system.
3. Check with your provider's support team. Some providers have specific settings for CLI presentation (e.g., "present main number" vs "present extension number"). Make sure the right option is selected.
4. Test with a mobile. Call your own mobile from your VoIP line and check what number appears. If it is wrong, you have confirmed the issue and can work with your provider to fix it.

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Problem 9: Calls Going Straight to Voicemail

What it sounds like: People tell you they called but your phone never rang. The call went straight to voicemail, or worse, they got a "number not available" message. Your phone is sitting on your desk, powered on, apparently working fine. But it did not ring.

What causes it:

• SIP registration timeout. Your phone has silently lost its registration with the VoIP server. It thinks it is connected. The server thinks it is disconnected. Incoming calls have nowhere to go, so they hit voicemail.
• Phone not re-registering after internet interruption. If your broadband drops briefly and comes back, your phone may not automatically re-register. It is connected to the internet but not connected to the VoIP server.
• Do Not Disturb enabled accidentally. It happens more often than you would think. Someone bumps a button on the phone, DND activates, and all calls go to voicemail.
• Call forwarding active. Someone set up call forwarding and forgot to turn it off. All calls are being forwarded to voicemail or another number.

How to fix it:

1. Check the phone's registration status. If it says "unregistered" or shows a warning indicator, restart the phone. Wait 2 minutes for it to re-register.
2. Set a shorter re-registration interval. In your phone's SIP settings, reduce the registration interval to 60-120 seconds. This means the phone checks in with the server more frequently, reducing the window where it could be silently disconnected.
3. Check for DND. Look for a DND indicator on the phone screen or a lit DND button. Press it to toggle it off.
4. Check call forwarding. In your phone's settings or your VoIP provider's portal, check if call forwarding is active. Disable any forwarding rules you did not set up intentionally.
5. Enable keep-alive. Some VoIP phones have a "keep-alive" or "NAT keep-alive" setting that sends periodic packets to maintain the connection through your router. Enable this if available.

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Problem 10: Poor Quality on Video Calls

What it sounds like: Video calls are pixelated, frozen, or constantly buffering. Audio is out of sync with video. The call quality is so bad you switch to audio-only, defeating the purpose of having a video phone system.

What causes it:

• Insufficient bandwidth. Video calls use significantly more bandwidth than audio-only VoIP. A standard definition video call needs 1-2Mbps in each direction. HD video needs 3-5Mbps. Multiple simultaneous video calls can saturate your broadband connection.
• Upload speed too low. Video conferencing is symmetric, you are uploading your video feed while downloading everyone else's. If your upload speed is only 2-3Mbps, one HD video call will consume most of it.
• WiFi congestion. Video is more sensitive to WiFi issues than audio. Even minor WiFi interference can cause video to freeze while audio continues.
• Hardware limitations. Older laptops and phones may not have the processing power to encode HD video smoothly. This is not a network issue, it is the device struggling.

How to fix it:

1. Check your upload speed. Run a speed test. If upload is under 5Mbps, you do not have enough bandwidth for reliable video calling, especially with multiple users.
2. Use wired connections for video calls. If possible, connect via Ethernet cable for video calls. This eliminates WiFi as a variable.
3. Close other applications. Cloud backups, large file downloads, and streaming services all compete for bandwidth. Close them during important video calls.
4. Lower video quality. Most video conferencing platforms let you reduce video resolution from HD to SD. This halves bandwidth usage with a modest reduction in quality.
5. Upgrade your broadband. This is the real answer for most businesses. If you are regularly making video calls and your broadband cannot keep up, you need more bandwidth, particularly upload bandwidth.

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Router Settings That Kill VoIP (And How to Fix Them)

Your router is the most overlooked piece of your VoIP setup. A misconfigured router causes more VoIP problems than anything else. Here are the three settings that matter most.

SIP ALG: Turn It OFF

SIP ALG (Application Layer Gateway) is a router feature designed to "help" VoIP by modifying SIP packets as they pass through the router. In theory, it fixes NAT traversal issues. In practice, it causes them.

SIP ALG is responsible for an estimated 50% of all VoIP problems. It mangles SIP headers, breaks audio streams, causes one-way audio, and prevents phone registration. It is the first thing every VoIP provider tells you to turn off. And yet it comes enabled by default on most routers.

How to turn off SIP ALG:

The setting is in different places depending on your router model. Log into your router's admin interface (usually by typing 192.168.1.1 or 192.168.0.1 into your browser) and look for SIP ALG in:

• Firewall settings, look for "SIP" or "ALG" checkboxes
• NAT settings, sometimes listed under "Application-level gateway" or "NAT helpers"
• Advanced settings, under "VoIP" or "SIP" sections
• Security settings, some routers list ALG features here

Uncheck/disable SIP ALG. Save settings. Restart the router. Test VoIP calls.

If you cannot find the setting, search for "[your router model] disable SIP ALG" online. Every common router model has instructions available.

QoS: Prioritise Voice Traffic

QoS (Quality of Service) tells your router which traffic is most important. Without QoS, all traffic is treated equally, your VoIP call gets the same priority as someone downloading a spreadsheet. With QoS, voice traffic goes first, and everything else uses whatever bandwidth is left over.

How to enable QoS for VoIP:

1. Log into your router's admin interface.
2. Find the QoS settings (usually under "Advanced," "Traffic Management," or "Bandwidth Control").
3. Enable QoS.
4. Add a rule to prioritise traffic on:
   • Port 5060 (UDP), SIP signalling
   • Ports 10000-20000 (UDP), RTP audio (check your provider's specific range)
5. Set these as "Highest Priority" or "Voice" priority.
6. Save and restart.

On more advanced routers, you can also prioritise by device, give your VoIP phone's IP address or MAC address top priority regardless of which ports it uses.

Firewall: Open SIP and RTP Ports

Your router's firewall protects your network from unwanted incoming traffic. But if it is too aggressive, it blocks VoIP traffic too.

Ports to open for VoIP:

Create firewall rules to allow both inbound and outbound traffic on these ports. If your VoIP phone has a static IP address on your network, you can restrict these rules to that specific device for better security.

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When to Blame the Provider vs When to Blame Your Setup

This is the question everyone asks. And the answer matters, because it determines who needs to fix it.

It is Probably Your Setup If:

• Problems affect all calls, both incoming and outgoing.
• Problems are worse during peak internet usage times.
• Problems started after changing your router, broadband, or network configuration.
• Problems affect all phones/devices, not just one.
• Your broadband speed test shows low upload, high latency, or packet loss.

It is Probably Your Provider If:

• Problems only affect calls to/from specific numbers or destinations.
• Problems started suddenly without any changes to your setup.
• Problems persist even with a direct Ethernet connection and no other internet traffic.
• Your provider's status page shows an outage or degraded service.
• Other customers are reporting the same issues (check Twitter/X or Trustpilot).

It Could Be Either If:

• Problems are intermittent and unpredictable.
• Problems affect only certain features (caller ID, voicemail, conferencing) but basic calls work.
• Problems only occur during certain times of day.

When in doubt, test methodically. Change one variable at a time. If the problem persists after you have optimised your router, tested with a wired connection, and confirmed your broadband is stable, it is the provider.

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When to Switch VoIP Provider

Not all VoIP providers are equal. Some have better UK infrastructure. Some have better support. Some have features that others do not. If your current provider cannot deliver reliable call quality after you have fixed everything on your end, it might be time to move.

Signs you should consider switching:

• Persistent audio quality issues that your provider cannot or will not resolve.
• Frequent outages. Any provider has occasional downtime, but more than 2 unplanned outages per year is unacceptable for a business phone system.
• Poor support. If you cannot get through to their support team when you have a problem, sound familiar?, they are not the right provider for a business.
• Missing features. If you need call recording, CRM integration, auto-attendant, or other business features and your current provider does not offer them.
• Price creep. If your bills have increased significantly without corresponding improvements in service.

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How Compare The Networks Helps With VoIP and Broadband

VoIP and broadband are inseparable. A great VoIP system on terrible broadband will sound terrible. A great broadband connection with a poorly configured VoIP system will still have problems. You need both to work together.

That is what we do at Compare The Networks. We do not just sell you a VoIP system and leave you to figure out the broadband. We look at the whole picture:

1. We assess your broadband. Is it fast enough? Stable enough? Does it have enough upload for the number of simultaneous calls you need?

2. We recommend the right broadband. If your current connection is not up to the job, we will recommend an upgrade. Our go-to for VoIP-ready broadband is Sky Business Broadband SOGEA 80/20 at £35+VAT, the 20Mbps upload handles VoIP beautifully, and the SOGEA connection means it works independently of any phone line.

3. We set up VoIP correctly. Router settings, QoS, firewall rules, SIP ALG, we configure everything so your VoIP works from day one.

4. We provide virtual landlines and full VoIP systems. From a simple virtual number to a multi-site phone system with call routing, voicemail-to-email, and auto-attendant. We match the solution to your business.

5. We support you when things go wrong. VoIP problem at 2pm on a Tuesday? Call us. We will diagnose it, is it the broadband, the router, or the VoIP provider?, and fix it. No hold music. No script-readers. People who actually understand VoIP.

We are OFCOM-regulated and rated 4.3/5 on Trustpilot. We have been setting up business communications since 2008. And we answer the phone.

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Frequently Asked Questions

Is VoIP reliable enough for a business?

Yes, when it is set up correctly with the right broadband. VoIP is now the standard for UK business telephony, especially with the PSTN switch-off making traditional landlines obsolete by 2027. The key is having sufficient broadband (10Mbps+ upload) and correct router configuration. With those in place, VoIP is as reliable as a traditional phone line, and significantly cheaper.

Do I need special phones for VoIP?

You can use dedicated VoIP desk phones (from brands like Yealink, Grandstream, or Poly), softphones on your computer (apps like Zoiper or your provider's own app), or mobile apps on your smartphone. Most businesses use a mix. Desk phones give the best audio quality; softphones and mobile apps give flexibility for remote and mobile workers.

Will VoIP work during a power cut?

If your broadband router loses power, VoIP stops working, just like a cordless landline phone would. However, VoIP has an advantage: calls can be automatically redirected to mobile phones during an outage. Most VoIP systems include failover routing that detects when your desk phone is offline and sends calls to your business mobile instead.

How many simultaneous calls can my broadband handle?

Each VoIP call uses approximately 100Kbps of upload bandwidth. With 20Mbps upload (like Sky Business Broadband SOGEA 80/20), you could theoretically handle 200 simultaneous calls. In practice, you should leave 50% headroom for other traffic, so 100 calls. Most small and medium businesses need 5-15 simultaneous calls, which any decent broadband connection can handle.

Can I keep my existing phone number?

Yes. You can port your existing landline or virtual landline number to your new VoIP provider. The process takes 10-15 working days for a landline port. During the transition, calls can be forwarded so you do not miss anything.

Is VoIP secure?

Modern VoIP systems support encryption (SRTP for audio, TLS for signalling), making calls as secure as any other encrypted internet communication. Make sure your provider supports encryption and that it is enabled. Unencrypted VoIP calls can theoretically be intercepted, but encrypted calls cannot.

What is the difference between VoIP and a virtual landline?

A virtual landline is a type of VoIP service, it gives you a geographic phone number (like a London 020 number or a Manchester 0161 number) that routes calls to your mobile, VoIP phone, or any other number. A full VoIP system adds features like multiple extensions, call routing, voicemail, conferencing, and more. Virtual landlines are ideal for small businesses that want a professional number. Full VoIP systems are for businesses that need a complete phone system.

How do I get started with VoIP?

Call us on 0203 006 1011 or get a free quote. We will assess your current broadband, recommend the right VoIP solution for your business, and handle the entire setup. If you need better broadband first, we will sort that too. Everything from one provider, with one point of contact.

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Fix It Today

You did not switch to VoIP to fight with technology. You switched because you wanted better calls, more features, and lower costs. And you can have all of that, once the problems are fixed.

Start with the broadband. Check your upload speed. If it is under 5Mbps, that is your problem. Fix that and most VoIP issues disappear.

Then check the router. Turn off SIP ALG. Enable QoS. Open the right ports. Use wired connections wherever possible.

If you have done all that and calls are still choppy, dropping, or one-way, it is time to call in help. That is what we are here for.

Call us on 0203 006 1011 or get a free VoIP assessment. We will diagnose the problem, fix what we can remotely, and recommend the right broadband and VoIP setup for your business. No hold music. No script-readers. Just people who know VoIP.

Compare The Networks, making UK business phones work properly since 2008. OFCOM-regulated. 4.3/5 Trustpilot. On your side.