Ultimate Guide to VoIP Phone Systems in 2019

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VoIP vs. Landline. What’s the difference?

Do you feel overwhelmed learning how to set-up VoIP for your company or office? If you are, you’re not alone. We’ve seen how common it is for administrators to be stuck on set-up and navigating through learning materials.

This guide is here to provide you a condensed resource, covering fundamentals of VoIP to actual set-up and purchase of a VoIP system.

What is PSTN?

PSTN, Public Switched Telephone Network , is the "traditional" telephony network. The origins of PSTN dates back to the invention of telephones. Thus, PSTN is also referred to as POTN ( Plain Old Telephony Network ).

For calls to be established over PSTN, endpoints must be connected to form a circuit.

The medium connecting these circuits can vary, including copper telephone wires, fiber optic cables, switching centers, cellular networks, and cable systems. This is where landlines come into play. Landline refers to circuits connected by physical wiring. The most common example being underground physical wirings that branch into homes.

A unique property of PSTN to note when comparing with VoIP is the concept of " circuit-switching ." Imagine circuits as railroad tracks. When a call is established, the track becomes a dedicated pathway for the two endpoints. For the entirety of the call, the dedicated pathway referred to as "open connections," will be consumed and won't be free until the call ends.

Calls and phone system that uses PSTN are also referred to as " analog calls " and " analog phone systems ."

What is VoIP?

VoIP stands for voice-over-IP. When a VoIP call is made, the call is transmitted over the Internet rather than traveling through physical circuits like in PSTN.

The transmission process used in VoIP is called "packet-switching." To illustrate VoIP, imagine the audio content of your call as a large piece of A4 paper.

When you speak on your VoIP phone, the audio content is processed by your device and torn apart into little individual pieces called "packets." The packets are then sent over your router and throughout a network of routers until it reaches its specified endpoint.

At the endpoint, packets are assembled back together into comprehensible audio.

Why VoIP - packet-switching vs circuit-switching?

In contrast to circuit switching in PSTN calls, packet-switching in VoIP is a much more efficient form of transmission.

First, packet-switching is used not only for VoIP calls but also for the pages you browse online and video and music streaming you consume. As long as you have a functioning Internet connection, you will be able to make and receive VoIP calls. Without needing a dedicated phone line (landline and cellular) are not required, VoIP is an opportunity to mitigate an additional cost item.

Secondly, as packet-switching differs from PSTN circuit-switching in that calls do not create an always-on "open connection." Data is only transmitted when sound is detected. This cuts down on the total resource usage, which is crucial as it consumes the same overall bandwidth availability.

Why should businesses consider switching to VoIP?

It's great to know that VoIP is more efficient than PSTN calls. Beyond the technical reasons, why are more businesses adopting VoIP?

Lower upfront set-up cost

Compared to analog options, making digital calls allow businesses to cut down the total infrastructure costs associated with calling operations.

As an example, to enable a company directory with assigned extension lines to each employee, analog options using landlines will require businesses to invest or rent multiple physical phone lines.

With VoIP, these infrastructure costs can be shifted over into the cloud or consolidated into a server with less hands-on maintenance.

Lower operational cost

VoIP lowers operational costs.

VoIP shines in particular for international calling. Using virtual numbers (DID), companies can route international numbers to their local phone lines. Doing so, when receiving or calling out, they are charged local rates, avoiding the pricy long-distance call rates on PSTN networks.

Better remote working VoIP makes working and collaborating with international offices much more feasible and direct since companies won’t be charged long-distance calling rates.

Mobility and Remote Working

The addition of softphones in VoIP also makes mobility and remote working easier. Employees are not locked in place at their workstation. They can easily access their work lines on any device whether it be their personal phone brought from their company’s BYOD or laptop.

More call functionalities and integrations

Using IP phones to handle calls also opens up more advanced call functionalities using in call and support centers. For instance, employees have access to call forwarding and transfer. Calls can be recorded with call metrics that can be fed back to your company’s CRM.

Contacts are also better managed. Using LDAP and Active Directory, contacts can be pulled from your company’s roster, Outlook and email directories.

Functionalities beyond calls, unified communications

Conferencing, screen-sharing and multi-participant meetings are now a standard form of collaboration for businesses. When presenting a demo, customers expect a screen-share link. When hosting a meeting, employees expect remote join options.

Using VoIP softphone clients, in particular, provides companies the opportunity to tie together these functionalities into one application. Employees can easily install the application on their mobile and desktop devices and instantly access their workplace communications.

What are some downsides to VoIP?

While VoIP is efficient and reduces operational costs, VoIP communication does have some drawbacks.

Dependency on Internet Connectivity

Since your communications will be sent over the web, reliable internet connectivity is crucial. Especially in cases of power-outages, your VoIP communications over the net will also go down.

Emergency Calling

VoIP was not designed with emergency calling in mind. With traditional landline phones, emergency calls can be easily traced to a calling source. However, in the case of VoIP calling, your real call address must be specifically set-up during your configuration. If it is not set up, emergency services will have no alternative method outside of verbal confirmation on tracking where your call is coming from.

Voice and Call Quality tied to Bandwidth Usage

To transmit messages, your company’s bandwidth is used. In scenarios of many users, this can be a problem as users draw from the limited pool of resources. This can deteriorate your call and voice quality. In contrast to dedicated landlines, your voice and call quality will be much more consistent.

What do I need to set-up VoIP for my business?

For the typical office that needs to make and receive business line calls, you will need the following core components:

  • Internet service
  • VoIP Provider
  • PBX or IP-PBX (to enable extension lines)
  • IP Phones (SIP Phones)
  • Headset

Internet Service Provider (ISP)

The reliability and speed of your internet service will directly impact your VoIP experience. Depending on the number of lines, concurrent calls and expected call quality, your Internet bandwidth and speed requirements will change.

What is bandwidth, upload speed, and download speed?

Bandwidth is a measure that describes the volume of data that can be transferred between your device and the Internet, expressed in kbps (kilobits per second), Mbps (megabits per second) and Gbps (gigabits per second).

Download speed is the data transfer speed from the Internet down to your device. Upload speed is the data transfer speed from your device up into the Internet.

How do I assess my bandwidth and Internet speed?

While ISP’s will promise various speeds, it is best to verify your Internet speed within your work environment. Factors like distance from your router and concurrent usage can affect your actual speed. You can test your Internet speed at the following free sites:

How do I estimate how much bandwidth I’ll need to support VoIP calls?

As a rule of thumb for acceptable call quality, your minimum upload or download speed (lower of the two) should be between 90kbps (kilobits per second) to 156kbps to support a single call. However, an additional margin should be added to this minimum as you will have other media contending total bandwidth use, such as online streaming and emails.

The recommended bandwidth capacity will also change as you increase the total number of expected concurrent lines. You can estimate the required bandwidth as follows:

Expected Concurrent Calls

Minimum Bandwidth Requirement

Recommended Bandwidth








1000kbps (1mbps)

5000kbps (5mbps)


3000kbps (3mbps)

15000kbps (15mbps)

In here, an additional margin of 5 times minimum was applied

What is network latency and how can it affect your VoIP quality?

Because VoIP relies on your Internet to pass data, delay between send and receive can affect the quality of your VoIP audio. Network latency should be particularly monitored when using cloud-based solutions to manage your call routing (hosted IP-PBX).

As a rule of thumb to remember, your network latency should not exceed 100 milliseconds. When latency exceeds this mark, you will have noticeable delays, causing participants to potentially speak over each other.

VoIP Gateways, IP-PBX, and VoIP Providers

This is the stage where most of the set-up occurs, and you will have to decide, how do you want your calls to be handled, do you want extension lines and which VoIP network setup is the most cost-effective for your usage volume?

Before diving into the different setup patterns available for VoIP, it is important to have a fundamental understanding of each infrastructural piece.

What are VoIP gateways?

VoIP gateways, also called PSTN gateways, are devices that convert incoming PSTN calls into VoIP. Some example of these devices are:

What are IP-PBX’s?

PBX’s, short for Private Branch Exchange, are switching systems in traditional telephony which allow businesses to manage their phone lines better. With a PBX, you can architect how extension lines are routed.

IP-PBX is the evolved iteration of traditional PBX systems, allowing you to do the same call routing for VoIP calls.

What are VoIP providers?

VoIP providers are services you can purchase. Instead of having to purchase and set up your own VoIP equipment, at a simple cost, VoIP providers will provide you gateways and IP-PBX.

VoIP providers simplify your deployment and maintenance process. In deployment, you will select your virtual numbers, set up line extensions and the additional call features you may want accessible from your VoIP phone such as voice mail, messaging and others.

The following is our curated list of the most popular VoIP provider, scored on ease of use and price.

Why do we recommend using VoIP providers for small-medium sized businesses?

In the context for small to medium-sized businesses, purchasing VoIP from VoIP providers is the way to go. The following characteristics make VoIP the perfect fit for SMB’s:

Reduces set-up complexity

Most VoIP providers have simple to use interfaces to make your setup process as easy as possible. This is a major plus since most administrators can be stuck and lost on the implementation phase.

Low upfront investment

Instead of having to provide the upfront investment for equipment like VoIP gateways and IP-PBX’s, companies can set up their VoIP network at pay-as-you-go or by user rates. VoIP providers often have a free trial period which is ideal for testing out your configurations before deploying across your team.

Easy scalability

When new employees are hired, the business can increase the number of extension lines needed.

On-going support

If there are any hiccups during your configuration stage, a customer support team is available to help.

Should you DIY and build VoIP from scratch?

VoIP technology has been around for a while and there open source solutions that you can leverage.

For your IP-PBX, you can build from scratch using open source software like Asterisk. Or, you can use a pre-packaged distro like FreePBX. The benefit of doing this instead is that you’re able to turn your unused computers into your VoIP servers.

What is SIP and why your VoIP systems should be using it?

SIP is a VoIP protocol, a networking language that allows your VoIP devices and servers to communicate with each other. SIP has a long history to date in VoIP. In addition, as it is open-source, a wide array of VoIP products use SIP. By using SIP, you will have large flexibility in choosing each VoIP infrastructural piece and easily shop around for a VoIP setup that best matches your budget.

You should be aware that there are proprietary protocols that strictly use their own protocols. The ramification is that you may be missing out on cost-saving opportunities as these proprietary manufacturers increase the price.

IP Phones

SIP phones, sometimes called SIP user agents, are the endpoint devices you will use to communicate. Amongst SIP phones, there are softphones and hardphones.

What are hardphones and softphones?

Hardphones are akin to your traditional phone with a handset and dial pad. At the core, they are computing devices that receive incoming digital packets and converts them to voice. Administrators will have to access them to configure their settings programmatically.

Softphones are the software counterpart to hardphones, except they do not have the physical presence of hardphones. Instead, softphones are applications that can be installed into your mobile and desktop devices.

Why use softphones?

A softphone not only mimics the features of a desk phone it also brings a wealth of additional functionality, with the features you’re familiar with, hold, transferring calls, multiple lines, voicemail, but with powerful new additions like presence, transferring to a colleague who is in a different city or at home, and notifications about incoming calls with rich information about the caller. You can also access a shared contact directory, keeping your personal contacts personal, but sharing your corporate directory right in your softphone.

How does softphone work?

A softphone runs on most devices and platforms. You can get softphone software that runs on Macs, Windows devices, Linux devices, desktops, laptops, tablets, smartphones and more. Most softphones can also run from a web browser, and as long as you have a microphone and speaker, you’re able to connect wherever you are.

A softphone uses software to mimic the functionality of a desk phone on your screen. The technology behind the software is VOIP, which stands for Voice Over Internet Protocol, which is the technology that allows you to make voice calls over the internet. All of the features of the phone are written into the software and provide a friendly and intuitive experience while making a call. Instead of remembering which button on your phone disconnects a call, and which one transfers a call, you can use a drag and drop interface on your laptop to connect your customer to an associate, put a call on hold, or direct a call to voicemail when you’re occupied.

Portability and Remote Working

One of the core advantages of a softphone is portability. You can run a softphone on your desktop, smartphone, and tablet and set up rules that ring your desktop or your smartphone based on your schedule. So in the morning calls will come to your desk computer, and in the afternoon or over lunch, calls come directly to your smartphone. This flexibility means you can work from home or while traveling with all the powerful tools you have at your desktop. You can stay in touch while in a meeting and know what calls and messages are coming through with a quick glance to your smartphone. If there’s an important client call you’re waiting for - you’re not stuck at your desk waiting on your phone to ring. You can take your phone with you wherever you go.

If you have staff that travel, work from home or remote locations the ability to take your work phone with you is a powerful advantage. You can be in an airport or at home and still have a call forwarded to you, or place a call that appears as though you’re in the office. Clients won’t know the difference, when they reach out to their key contacts, they’ll be available at the same contact information, no matter where your team is.

Keeping Cell Phones Private

A key advantage of a softphone system is that you can keep your staff cell phones private. Your team will no longer have to share their personal cell phone numbers and use up their minutes for work, they can use softphone software on their smartphones to receive and place calls. They can also control their availability with settings to identify when it’s time to focus on family or personal time. When they set their status to away, the work phone won’t ring but will go directly to voicemail, or be routed to another available individual when a team member needs some personal time. Using a softphone your team can also place outgoing calls from their smartphone that display to your clients and partners as though they are coming from a work phone. So your team has the convenience of their device or smartphone of choice, but the protection and professionalism of a work number to your customers.

Advantages of a softphone over a desk phone

There are a number of features that a softphone provides that are a significant advantage over a desk phone.

Shared contact lists

You can subscribe to a company contact list, or share your contacts with coworkers. If you’ve ever tried to find the cell phone number for a client that you know your college has, this is a tremendously useful feature.


Softphone systems show when your team is online and offline, as well as when they are busy or in a meeting. Instead of sending a message and waiting for someone to respond - when they’re getting a coffee, away at lunch or in a meeting, you can quickly identify when someone is available or not. In addition, you can see when they’re in a meeting or on a call, and reach out through instant message to see if they can respond to a quick request. Presence empowers you to make good communication decisions when reaching out to your team.


Softphones allow you to take your communication with you wherever you go. You can run calls from your laptop, tablet or smartphone. You’re not tethered to your desk, waiting for an urgent call, you can head to the gym, get lunch or attend an important meeting, and step out just for the moments you need to address that important call. You can also keep tabs on communication wherever you are and respond to colleagues quickly through text or a video call - wherever your travels take you.


Voicemails are a great improvement on softphones, allowing you to get an audio file pushed directly to your email, or as a push notification on your mobile phone. You can get a transcription of the contents of the audio file, so if you’re in a meeting, you can quickly glance at the message, and by reading the transcript, identify it’s urgent and worth stepping out of the meeting, or if you can follow up after.

Work better with better tools

Another important advantage of softphones is that they give your team the tools they expect in a modern workplace. Technology is moving forward quickly, and our expectations as consumers are that we can have everything on our smartphones. Your employees of all ages are likely expecting more from their workplace, and want a solution that allows them flexibility in the way they communicate with each other and with clients. Some of the key features that teams love in a softphone are:

  • Drag and drop call transfers
  • Visual Voicemail
  • Voicemail in email
  • Incoming call and voicemail notifications on their smartphone
  • Presence
  • Video calls and conferences
  • Easy instant call bridges
  • Switching from music to calls quickly with the same headset

You have a team of smart people working for you. Providing softphone systems allows your team to work the way they expect to. Modern cell phones and laptops are tools we carry with us wherever we go, and softphones allow you to bring your work phone along with you, wherever your travels take you.

Of course, there are many more reasons to selecting softphones over deskphones. Read more in our following article!

What do I need for a softphone?

The core requirements for a softphone to work are a PC or laptop with microphone and speakers, or a headset. You can also use a modern smartphone or tablet. You’ll also need a strong bandwidth or an internet connection. You’ll also need to set up an account with a service provider and download a software program to be your softphone. Bria has a great integration of software and service through their Teams solution.

The technical details

If you’re the technical type and want to know the bits and wires that power a softphone, most systems run on VOIP and use a few protocols to make their connections. Session Initiation Protocol (SIP) was one of the first protocols that were created to allow voice calls over the internet on VOIP. VOIP is the layer that allows a voice to be converted to information and sent across the internet. SIP is the protocol that allows you to dial numbers, see if someone is available, conference a 2nd line in and all of the other features that a typical phone system would do. Extensible Messaging and Presence Protocol (XMPP) was created a little after SIP, and is more focused on the Instant Messaging and presence part of softphones. Most software allows you to call, video chat, message and see if a user is online or offline. The video/messaging/presence is the strength of XMPP while the calling/connecting/continuity is the strength of SIP. They share the majority of features, but depending on the profile of your organization you may want to research further on SIP or XMPP as a provider or find a solution that blends both options. Inter-Asterisk Exchange (IAX) is a more modern protocol built on the Asterix platform that again provides similar features. AIX has a binary versus a SIP which has a plain text protocol. If you’ve read this far and you’re eyes are glazing over - no worries. Find a softphone provider and they’ll take care of all these details for you.