Beginner's Guide to VoIP Call Quality & VoIP Troubleshooting

June 10, 2018 12 min read

Cameron Johnson

Cameron Johnson

VoIP Call Quality

There’s a good chance your business is already using VoIP phone service. If not, you should be for the VoIP call quality alone but there is more.
In 2017, an estimated 37% of businesses were already using VoIP, and this number is growing fast. Here’s what you need to know.

What’s so good about VoIP phone service and VoIP call quality?

So. Many. Things. Here are just a few.

  1. Save big money
    • No more individual phone lines. This translates to huge savings on monthly phone bills.
    • Remote workforce. Real estate and overhead costs are reduced with remote workers.
    • Maintenance costs. VoIP doesn’t work like a traditional phone system. There’s less hardware maintenance required. And when there is a problem VoIP troubleshooting can often be handled remotely, without a pricey service call.
VoIP time savings compared to landlines

  1. Portability and accessibility
    • If you’ve got an internet connection, you can use your VoIP phone. Your number follows you, so there’s no need to give clients your personal cell or home phone numbers. Whether you’re at home, in an airport, or at Starbucks, you can make and receive calls.
  2. Call quality
    • With a strong internet connection and great bandwidth, VoIP calls sound as good – or better – than traditional phones.
  3. Flexibility
    • Hiring a bunch of short-term contractors to make calls? No problem. VoIP systems allow you to add unlimited users. Your only limitation is network bandwidth.
  4. Video calls and conferencing
    • Video capability is already part of VoIP. No add-on services or tech required. Get to know your remote staff better or chat with your newest client face to (video) face.

These are all great features of Voice over IP service. But what about the users, your employees?
Imagine a world where your staff could move freely around your office.
They’re doing video training in a conference room or closing a deal in the lounge. They’re not chained to a desk and a bulky handset.
The guy with a sore throat can go home and finish his day there. He can take his work, and his phone, with him.
Call center leaders can easily monitor queues and call traffic. And they’ll have the freedom to do it from the office or their couch.
VoIP Call Analytics


Gone are the days of convoluted call and queue routing maintenance. Your leaders can handle queue setup and call routing all by themselves. There’s no need to hire someone for complicated programming.
You can set new, lofty key performance indicators. Those KPIs will be no problem. Your team has the tools and flexibility to give your customers excellent phone service.

Nextiva gets it

And we want to hook you up, too. Our world-class team can show you how a VoIP system will transform your business.
There’s no tech-speak here. At Nextiva you’ll get clear, easy-to-understand information. We’ll speak your language.
Nextiva provides amazing service.

But can I trust VoIP service?

unified communications and voip timeline

The short answer is yes The great thing about VoIP? It’s not new – And that’s a good thing.
Every time Apple releases a new iPhone I hear people say, “I’ll buy it in a few months. You know, once they’ve worked all the bugs out.” I usually roll my eyes when they say it, but they’re not entirely wrong.
VoIP was born in 1995, making the idea of unified communications a reality. It started as a simple software that allowed two computers to connect their users through the computer’s speakers. The interface was clunky, and its functionality was limited. But the technology was alive and growing.
By the time VoIP became widespread in the mid-2000s, the functionality had expanded. Calls were clearer, the software was flexible, and things like voicemail and video chat were added. The bugs were long gone. And so were the office closets packed with landline cables. Like any great technology, there can be a few problems with VoIP phone systems. Good thing VoIP troubleshooting is a cinch.
Before we jump into fixes for VoIP issues, let’s make sure we understand how it works in the first place.

What is VoIP, really?

VoIP is an acronym for Voice over Internet Protocol. 
When you’re talking over a VoIP line, your voice is taken in tiny analog chunks and turned into numbers. Those numbers are grouped together into data packets containing about 20 milliseconds of your voice.
These little data packets are transmitted across the internet to the receiver’s device (the person you’re talking to.) The data is transferred back to an analog signal and the audio is played.
This process happens at lightening-speed, so your conversation flows like normal.
Most of this technical stuff is happening at the hosted PBX. Simply, a hosted PBX the place where your VoIP service is handled. The PBX takes care of routing and maintenance. The staff knows how to troubleshoot VoIP issues and fix them. They also provide technical support and training.
Some companies, like Nextiva, offer cloud-based IP PBX. This virtual hosting gives customers even more flexibility.
how VoIP works diagram

Is this how it works in my business, too?

Yes. VoIP technology is essentially the same whether you’re using it on your home phone or in your business. When businesses use VoIP their world is instantly expanded.
No more workers tied to their desk phones. No more giving out personal cell numbers to clients. No more fumbling with bulky conference call speakers. Because Voice over IP doesn’t need analog phone lines, it’s easy to integrate business lines, mobile lines, conference lines, and workers all over the world.
Setting up a VoIP phone system is easy. In fact, in less than an hour, you can be up and running. It’s even faster if you are set up virtual phone system for a remote team. Without hardware, you can be online within minutes. Just download an app, sign in, and you’re done.

So, what are the VoIP issues?

You can count the common VoIP problems on one hand. VoIP problems are easy to troubleshoot. And because this is proven technology, they’re usually straightforward to fix.

Issue #1: Jitter

acceptable network jitter is below 30ms

What is jitter?
Remember the data packets I told you about earlier? Well, there are a ton of them flying around the internet. In a perfect world, every data packet would reach the correct destination in the correct order. In reality, that doesn’t always happen.
packet delay from voip network jitter
Related: What Is VoIP QoS & How Can It Improve Your Call Quality?
Jitter happens when a data packet is delivered late. There are multiple paths a data packet can take through the interwebs. Not all packets take the same path. They’re not linked together like a train on a track. It’s more like a bunch of individual train cars on different tracks working to get to the same place in the right order.
How does jitter affect my call?
If there’s a lot of jitter, your VoIP quality can suffer. Pieces of missing audio can make your call sound garbled or jumbled. You could end up sounding like a cyborg, which is cool but probably not good when you’re on a work call.
A certain amount of jitter is considered standard. It’s usually so slight, your call quality doesn’t suffer at all. There are certain levels of jitter that are expected and acceptable.
How much jitter is acceptable?
The general rule: 30ms of jitter or less is okay. At 40ms of jitter, you’ll have serious call quality issues.
To understand what this means, think of our train car example. Car A and Car B are cruising along with no problem. Car C gets lost but makes a fast recovery. He’s back on track and in line with Cars A and B in less than 30 milliseconds. In the end, no one will notice he got lost.
But if Car C gets so lost it takes more than 30 milliseconds to get back on track, now the cars are out of order. There’s an obvious error.
In terms of your phone call, if a data packet is lost or delayed but quickly recovers, you probably won’t even notice. But if there’s a more serious delay, you’ll hear it.
Can it be fixed?
The first step in troubleshooting jitter is checking the network. Like anything else that relies on the internet, VoIP quality needs a good connection. We’ll talk about that more a little later.
The next step in troubleshooting is considering a jitter buffer.
A jitter buffer is an area where data packets are collected and stored, then sent out in regular intervals. The jitter buffer should keep data packets moving along in a regular, orderly fashion. This keeps your VoIP call quality where you want it to be.
voip jitter buffer bell curve
At Nextiva, our devices provide a small amount of jitter buffering right out of the box. This is usually enough to waylay any quality issues. A lot of jitter buffering can cause audio delays, though. We don’t recommend our clients jump into a high level of buffering without additional troubleshooting.

Issue #2: Latency

What is latency?
Latency is lag or delay. It’s the lag time between a caller speaking into their phone and the person on the other end hearing the audio.
Latency causes calls to sound echoed. Severe latency can cause users to speak over one another because there’s a delay in hearing the other person. Latency doesn’t affect the quality of the audio itself, but the ability for callers to communicate clearly.
Effective Latency
Because latency and jitter are related, they’re measured together. The metric is called effective latency.
It’s measured using these figures:

  • Amount of latency in milliseconds
  • Amount of jitter in milliseconds
  • 10.0 – This is the amount of time allowed for the device to compress/decompress the data

Here’s the equation:

effective_latency = latency +2*jitter + 10.0

For those of us who didn’t do well in Algebra I, here it is again:

Delay + jitter x 2 + 10.0 = effective latency

Why are we multiplying jitter by two? Because it’s a big deal. It can cause poor VoIP call quality.
network jitter and latency between devices
So how much latency is acceptable?
The general rule is 250 milliseconds, on the high end.
But this is subjective. An international call is bound to have more latency than a call across town. Users typically know and accept this. You wouldn’t end a call to Sri Lanka because of a little lag. But you might hang up if there’s lag when you’re talking to someone in your building.
Can it be fixed?
Latency can be caused by a few different issues. Troubleshooting can track these down pretty quickly. In many cases, it’s caused by network congestion.
Congestion across the network not only causes latency but can also contribute to jitter. Prioritizing VoIP data across your network can greatly reduce this.
A high-quality VoIP router can get those data packets moving the way they should. A great router can reduce all manner of problems with VoIP phone systems.

Issue #3: Packet loss

What is packet loss?
Let’s revisit our data packets again. You remember – The little 20 millisecond chunks of your voice traveling from speaker to listener.
Packet loss is:

  • Data packets that are completely lost and never reach their destination, or
  • Data packets that arrive so late they’re discarded, or
  • Data packets are discarded because they contain errors.

When packet loss is high, call quality is negatively affected. Pieces of your audio are literally missing, making the conversation hard to understand.
How is packet loss measured?
The VoIP industry created the Mean Opinion Score (MOS) as a way to measure VoIP call quality. This score is based on the user’s opinion of the call quality.
Here’s a look at the chart.









Perceptible but not annoying



Slightly annoying






>Very annoying

Can it be fixed?
Troubleshooting VoIP packet loss starts with checking your network.
A congested network can cause packet loss. Downloading files, sending large emails, and making phone calls with VoIP can put a serious strain on your bandwidth. (This is why you shouldn’t stream Netflix at work.) When your network starts reaching its maximum bandwidth, it doesn’t behave well. Files start containing errors or they’re squeezed out and lost. Hence, our missing data packets.
A few simple things can help:

  • Don’t rely on a Wi-Fi internet connection. Your cell phone’s hot spot isn’t going to cut it.
  • Make sure you have adequate bandwidth. Don’t try to use VoIP on a dial-up connection.
  • Minimize network congestion. Downloading music, streaming a movie, and sending a huge email attachment simultaneously are not advised.

Issue #4: Poor internet connection

I already know I need a good internet connection
Yes, you probably do. But did you know most internet service providers aren’t designed to handle VoIP traffic?
The average ISP is optimized for web surfing and uploading/downloading files. Sending audio data packets requires certain protocols that your ISP might not be providing.
A VoIP system requires a strong, fast internet connection with an adequate bandwidth. Without it, you can expect to have the VoIP quality problems we’ve talked about.
How strong is your connection?
Pop over to Nextiva’s speed test tool to check just how strong your connection really is.

speed test to measure voip call quality

Here’s what you’ll learn about your network:

  • Download and upload speeds
  • Ping and jitter times
  • Overall capacity

I failed the speed test. What can I do?
This one’s simple. Upgrade your service.
Nowadays, most ISP’s offer business-class service packages. These are optimized for – you guessed it – businesses. With higher bandwidth and more robust service, business class internet service should meet the needs of a VoIP system. If your ISP can’t meet these needs you should seriously reconsider your provider.

Commonly asked questions

I already told you VoIP troubleshooting was simple. So simple, you can do a lot of it yourself. (But remember – If you need help, Nextiva provides amazing service!)
Let’s take a look at five common questions VoIP users have. We’ll throw in the answers for free.
Q: I’m not getting calls.
A: Common reasons for not receiving phone calls are:

  • Power outage
  • No internet connection
  • Firewall blocking signal

Power outage – If your power is out, your VoIP system, just like any equipment, will not function. Most businesses rely on battery back-ups or generators to ensure they never totally lose power. If it’s an isolated power loss, check your cords and outlets.
No internet connection – If your internet is down, all your network-reliant processes are down, too. First, do some visual troubleshooting. Make sure nothing is unplugged or otherwise out of order. Then do a power cycle. If you’re still without an internet connection, contact your ISP.
Firewall blocking signal – Be sure your router’s firmware is up-to-date. Many firewall issues can be with a simple router update.
If you’re still having problems, get help with your VoIP troubleshooting. Reach out to your VoIP provider’s help desk.
Q: My internet is working but I can’t make calls. There’s no dial tone.
A: This is often an equipment issue.

  • A device has lost power
  • A phone cable or splitter is defective
  • Another device or system is interfering with the VoIP

A device has lost power – Be sure your handset has power. If you’re using a wireless headset, make sure it’s charged.
Defective cable or splitter – Check your cables. Unplug them and plug them back in. Try switching out the cable.
Something is interfering with the VoIP – Third-party voicemail and caller ID can interfere with your VoIP service. Security systems can also cause VoIP issues. Try disabling these features.
What if I’m still having issues?
We’re here! Contact Nextiva to learn how switching VoIP providers can help your business. Don’t give up on VoIP because of a few problems.
Switching phone systems can be a headache – with the other guys
Nextiva’s amazing service makes the transition easy.

You might feel nervous about switching to a VoIP phone system. After all, your old system works fine. But is it giving you the chance to completely change the way you do business?
The disasters you may have heard about in the early days of VoIP technology are long gone. Technology has advanced, making VoIP a safe and stable solution for business. Whether your team is 10 people or 10,000, there’s a VoIP solution for you.
Your phone system should be a tool for your business, not a burden. The Nextiva team values your business. Our outstanding support saves you time and energy. You spend time growing your business – Nextiva will spend time giving you a powerful VoIP phone service to do just that.
No one should have to worry about their phone system. If you do, it’s time for a change.
Did you know Nextiva has some of the highest reviews and happiest customers in the industry?
The support team at Nextiva prides itself on making the best use of your precious time. 95% percent of their support calls are answered by the second ring and you’ll rarely be on hold. How’s that for caring about your time?
 When you reach out to Nextiva, you can count on learning about customized solutions for your business.
Check it out for yourself. Customers love Nextiva. Here’s what they’re saying.
Learn more about how Nextiva can take your phone system – and your business – to the next level.

Cameron Johnson


Cameron Johnson

Cameron Johnson is a market segment leader at Nextiva. Along with his well-researched contributions to the Nextiva Blog, Cameron has written for a variety of publications including Inc. and Cameron was recently recognized as Utah's Marketer of the Year.

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