Everything You Need to Know about VoIP Hardware Requirements

With the recent announcement by BT that the legacy PSTN and ISDN telephony services are nearly being phased out, there has been a lot of discussion about VoIP and VOIP hardware its merits as the able successor of the two networks. If you’re already thinking about making the leap to deploy this modern system, there are a few decisions you need to make. The most important one is choosing a reliable service provider to connect your business to the VoIP network. The next most important decision is to choose a quality hardware setup that allows you to communicate clearly with your callers.

Here, we’ve prepared a detailed list of all the equipment you need for your VoIP telephony system. Worth mentioning is that you possibly won’t need everything we list here. Also, Metrotech takes care of nearly all of these tools during installation so you hardly have to worry about them.

Having clarified that, let’s now get started!

Hardware for Hosted VoIP

IP Phones

What is an IP phone?

When using Hosted VoIP for your telephony needs, an IP phone is the gadget or system that you dial into to facilitate a call. It has the physical and virtual interface that you’ll be interacting with as you receive or make your calls over the VoIP infrastructure.

The IP phone possesses a mouthpiece, an earpiece, while some models have a second speaker so that you can hear and talk to the other party during a VoIP call. These devices come in various sizes depending on the manufacturer, but importantly they are portable, unlike ISDN landlines.

In addition, IP phones have all the important features of a telephone system including call recording, call waiting, call diversion, call reports, etc. You can access and view these functions through a display screen that can be found above the call buttons.

Types of IP Phones

IP phones can be classified into two main categories namely:

  • Purpose-built Hardware Device
  • Software-based Softphone

Purpose-built Hardware Device (SIP Phone)

This is the commonest type of IP phone that resembles a typical telephone or cordless phone. It is popular for its compatibility with PSTN phones although it requires an Analog Telephone Adapter (ATA) to function properly. We’ll discuss what ATA is later on in this article.

Just as the name suggests, a purpose-built VoIP phone is dedicated to the call function. Put otherwise, the device behaves like a normal phone but with features that are primarily designed for VoIP calls. It differs from the softphones in the sense that it connects directly to a data network as opposed to a standard PSTN line. In addition, it has an integrated mini hub whose function is to share the network connection on your computer or other internet devices.

IP Phone subtypes include:

Conference Phones

This is a hardware phone designed to manage calls between multiple parties. It has a conference bridge that allows you to add members to the group call.

Wireless IP Phone

Designed to work with PSTN lines and connect to Wireless Hotspots, this IP phone is ideal for mobile businesses. As long as you have a viable wireless internet connection, you can make VoIP calls with it.

Software-Based Softphone

Instead of having a physical interface, the software-based softphone features an application that you can install on internet devices such as smartphones. This type of IP phone utilises the host’s hardware such as speakers and microphone to facilitate calls. Its main edge over purpose-built SIP phone is that you can switch between software vendors as you deem convenient or as your business demands change.  Moreover, the majority of softphones can easily be tweaked to support video calls.

How IP Phones Work

An IP phone works by reading and converting human’s voice into a digital signal which is then transmitted over the network as data. Put simply, these phones capture your telephone conversation, routes it to a VoIP system using a network cable which then connects to the internet for the voice data to reach the other party. It captures your voice using the microphone hardware that’s inbuilt into the phone’s motherboard. In reverse, it receives digital signals from the other party, converts them into an analogue form which basically is human language.

Features to Look for When Choosing the Best IP Phone Options

Call Switchover

Call Switchover allows transfer of calls from one gadget to another without the other party noticing the switch. This feature is particularly helpful to customer service agents, who in the face of technical questions, can connect callers to other more knowledgeable or specialised professionals.

Follow Me

This feature allows users to be reached even when they’re far from the office phone. With it, you can configure your IP phone to ring your other pre-specified numbers before going to voicemail.

Hunt Group/Ring Group

Hunt group feature facilitates routing of a call from one extension to another in a call centre until it’s responded to. On the other hand, Ring Group feature allows for simultaneous calls to be made to multiple extensions until anyone in the group answers it.

 Least Call Routing (LCR)

This cost-saving feature routes calls via the cheapest path in the list that you’ve pre-specified. It’s best suited for individuals or businesses who occasionally make long-distance or international calls.


This feature is important in situations which you need the IP phone to adapt to your work environment. It allows you to program handset keys to perform particular tasks such as call forwarding or voicemail.

CRM Database Integration

If your business has prospect information stored in a CRM system database, this feature makes the IP phone search automatically for the caller ID in it. With this function, you can find all the relevant info you need to handle each customer satisfactorily.

Analog Telephone Adapter (ATA)

If your organisation still prefers to retain the analogue devices used by the traditional telephone systems such as ISDN, it can do using an Analog Telephone Adapter. This device connects fax machines, traditional telephone systems, and printers to the digital phone system or VoIP telephony network.

It sits between the telephone jack (interface connecting user to a telephone network) and an IP network (internet interface). An ATA can be locked to make it incompatible with VoIP services provided by other competitors.

How ATA works

An ATA has an Ethernet port, USB port, Power line, and several foreign exchange station (FXS) phone ports. For this, it’s able to:

  • Access the VoIP server
  • Connect to the telephone system
  • Control the dial tone
  • Provide caller ID data via line signalling
  • Connect to the Ringing Generator.

The Ethernet port allows the adapter to be part of the IP network which shares an interface with VoIP server. Its USB port too can be used to connect to the IP network but on devices that feature USB ports such as computers. However, the adapter doesn’t necessarily require a computer to access the VoIP server as it directly connects to it via the Ethernet.

Communication with VoIP server depends on Session Initiation Protocol, Skinny Client Control, Inter-Asterisk Exchange (IAX), among other protocols to communicate with the VoIP server. It uses voice codecs to convert voice signals into digital forms and vice versa. The adapter uses about 5 watts of electricity for its ordinary function.

Features to Look When Choosing the Best ATA Option


A reliable ATA possesses both the LAN (RJ-45) and telephone network (RJ-11) ports to facilitate communication between the two systems. Having a USB port is a plus since computers and other USB devices can be added to it for increased function.

VoIP Protocols

There are various VoIP protocols you can use today including SIP, IAX, SCCP, H.323, etc. The more protocols an ATA supports, the higher the chances that it’s compatible with different VoIP technologies.

3-Way Conferencing

An ATA supporting 3-way conferencing is able to facilitate a simultaneous call to multiple people which is beneficial in a business that deals with multiple staff members and clients.

Call Switching

An ATA with this feature can switch between VoIP and PSTN as need arises and still remain a bridge to the two networks.

Voice Quality

Which quality of voice are you looking for in your business? ATA manufacturers have diverse voice technologies including Digital Signal Processing which serve audio in HD.

Standard Functions

These include call transfer, caller ID, call forwarding, call waiting, and recording which increase convenience in the usage of the telephone system.

VoIP Headsets

A VoIP headset is an audio device designed to facilitate hands-free communication by conveniently placing the IP phone speaker and the microphone next to the ear and mouth. In a business environment, the VoIP headset seeks to offer the following benefits:


This tool can help to eliminate the need to carry the IP Phone around during exchanges as long as you’re within its wired or wireless transmission range.


Depending on the design, the VoIP headset can be placed over your head or plugged into the ear to facilitate a hands-free conversation. With this, you can multitask which improves productivity during calls.

Audio Clarity

Most modern VoIP headsets come with a noise cancellation feature which improves the quality of voice signals. You can work in a loud environment without you or your caller getting distracted.

Types of VoIP Headsets

Monaural Headset

This headset type is designed to be worn on one ear. It’s ideal for environments where split attention is necessary meaning you’re listening to the person on the line as well as people around you.

Binaural Headset

This device is designed to be worn on both ears as it gives voice output on both channels. It’s best for loud environments or where maximum attention to the person on the line is needed.

Wired Headset

A typical wired headset is connected to an amplifier, computer or other peripherals which are then connected to the IP phone. It uses a 3.5mm copper wire for voice transmission.

USB Headset

With the USB headset, digital data can be obtained directly from the IP phone as a result of the architecture of the cable (i.e. four wires with dedicated functions).

Wireless Headset

This headset offers the convenience of mobility, allowing you to move to locations far from the IP phone. It uses two primary technologies to achieve the wireless function; Bluetooth and DECT. Most of them work within a 10-meter range. 

How VoIP Headsets Work

The VoIP headsets can be connected directly to the IP phone or an intermediary device such as a computer. The voice signal from the IP phone travels via wired cables or over the air using technologies like Bluetooth or infrared to reach your ear. Similarly, it captures your voice via the microphone which then carries it over the transmitting channel towards the IP phone or intermediary. The process takes microseconds which means you’ll hardly notice any significant delays in communication.

What is a VoIP Router?

This is a device that connects a VoIP phone to the IP network to allow for digital transmission of voice data. Most come with the RJ-45 LAN port which takes in the Ethernet cable from the IP phone or ATA to facilitate transportation of voice data on the internet. You can connect one or several IP phones to the Wide Area Network (internet) using one VoIP router if it has more than one RJ-45 Ethernet port.

How a VoIP Router Works

When you initiate a call, the IP phone establishes a connection to the internet to reach the number you’re calling. This involves transporting data packets via the VoIP router which happens to be on a local area network, to wide area network, and finally to the destination. Once the connection is established and the person you’re calling picks the call, your voices are converted into digital data. The data is handled like any traffic using common internet protocols such as TCP and UDP while consuming the available bandwidth.

Unlike an ordinary router, a VoIP router can be configured to prioritise voice traffic and to eliminate bandwidth competition by other data types. In turn, this guards voice calls from packet dropping and possible interruption of communication when the network is busy. This feature, which is known as traffic shaping, can be enabled or disabled on the VoIP router settings. 

Features to Look for When Choosing VoIP Routers

Quality of Service

Also known as traffic shaping, this feature facilitates control of the amount of bandwidth each data type gets on the router. With it, you can prioritise your voice data over other data packets for increased reliability during a call.


This feature facilitates the separation of voice and other data types on your router. When enabled, you can partition network devices into subgroups and set bandwidth allocation limits. The feature allows for dedicated VoIP traffic up to a specified limit.


Protocols are sets of instructions on your router that help to control multimedia capabilities over the network. Common protocols for Hosted VoIP include SIP and H.323. You can use this feature to increase control over call sessions. This is key in ensuring sessions are established properly or terminated in the shortest possible time. Application Layer Gateways (ALGs) are known to block common VoIP protocols which is why it’s important to confirm that your router has this feature.

Radio Band Frequency

A router can have dual or tri-band frequencies to control connection speed to WAN. Dual-band routers have radio frequencies of 2.4GHz and 5GHz while Tri-bands come with an extra 5GHz channel. With such routers, you can specify the frequency preferred for each data type. 5GHz routers are the best option for hosted VoIP technology.

Hardware for IP PBX

Power Over Ethernet (PoE) Devices/Switches

In IP PBX infrastructure, Power over Ethernet refers to systems/standards which allow data as well as electric power to pass through a twisted pair Ethernet cable. The single cable powers the peripherals in a networking infrastructure and provides a channel through which data can pass. The peripherals can be VoIP phones, VoIP routers, or Wi-Fi Hotspots on a network.

Switches, on the other hand, are interfaces where PoE devices are connected to and which provide power and facilitate the movement of data across the network. They act as physical gateways with ports where Ethernet cables are inserted to pass data to a network.

How PoE works

Power over Ethernet works by running tiny electrical currents through an Ethernet cable connected to a device such as a router. When the current arrives at the port of the attached device, it powers it up. The methods used in the transmission process include Alternative A, B, and 4PPoE. All of these methods are standardised by the Institute of Electrical and Electronic Engineers (IEEE) 802.3 who also define the wired Ethernet’s physical and data link layers.

These techniques control the speed of data transfer and power through the twisted wires of the Ethernet. Speed variants for data can range anything between a few Mbps to several Gbps while power is measured in term of watts per second.

Types of Power over Ethernet (PoE)

There are two main types of PoE namely:

  • PoE
  • PoE+.

PoE is the standard version which most VoIP phones utilise while PoE+ is the newer version of the Power over Ethernet system. The major distinction between the two is the amount of power transmittable over the Ethernet cables.

PoE transmits up to 15watts while PoE+ up to 25watts. For the majority of VoIP devices, PoE serves the power function sufficiently. PoE+ devices work with standard injectors (switches) which you find on VoIP routers although power flow is somehow restricted to match up to the PoE level.

Types of PoE Switches

There are three main types of PoE switches namely:

Managed PoE Switch

This is designed for data centres and enterprise networks where high levels of management, control, and network security are key. The switches can be set to prioritise various types of data traffic, monitor traffic as it goes through the PoE system, and partition a network into subgroups.

Hybrid PoE Switch/Web Smart

Built for VoIP and smaller networks, a Hybrid PoE switch offers Quality of Service and VLANs. With it, you can set up virtual networks and configure ports on your LAN which will purposely be used by various VoIP services.

 Unmanaged PoE Switch

Ideal for home networks, this switch offers the benefit of plug and play function. It does not require much networking knowledge to configure or operate compared to the other two types of PoE switches. The downside is that it doesn’t come with any inbuilt security features.  

Features to Look for When Choosing the Best PoE Switch

Ports on Switches

Ordinary switches have interfaces with between 4 and 54 ports. Your choice of the number of ports depends on the PoE devices you require in your working environment. A good practice is to go for switches with as many ports as you can afford so that all your VoIP devices simultaneously benefit from the network.

PoE Switch Speed

The 10/100mbps interfaces are quickly getting phased out by the Gigabit interfaces which deliver higher data speeds on the network. If you’re using 4G or a newer broadband, your best option is a Gigabit switch interface.


PoE switches are vulnerable to network failures which can destabilise the whole VoIP infrastructure. Instead of picking a switch with, for example, 16 ports, how about you go for two switches each with 8-port units. That way, only half of the network is affected when a catastrophic failure occurs.

VoIP Gateway

This is a piece of network hardware that’s designed to convert traditional telephony connection into modern VoIP connection. The conversion uses Session Initiation Protocol which allows digital packets to pass through an IP network. In reverse, the VoIP gateway is capable of converting digital packets into traditional telephony traffic for movement across the Publicly Switched Telephone Network (PSTN).

How a VoIP Gateway Works

In essence, the VoIP Gateway is the bridge sitting between PSTN and an IP network. It works by converting voice traffic into a proper form so that the destination device can decode it. When a voice signal originates from the PSTN, the VoIP gateway reads, converts it into a digital form, and using a codec, compresses it into a series of data packets ready to be transported over the existing IP network. Example of voice codecs that your VoIP Gateway can use include GSM, iLBC, and G.711.

When digital packets of the voice traffic originate from the IP network, the VoIP Gateway decompresses them and then converts them into analogue voice signals ready to be transported over PSTN. Here at Metrotech, we implement SIP to facilitate VoIP services on your IP phones and devices.

Types of VoIP Gateways


This type of VoIP Gateway connects your VoIP phone system to the traditional analogue telephones. It’s available in two forms namely FXS gateway and FXO gateway. The former connects analogue phones and fax machines to your VoIP phone system while the latter the VoIP phone system to the PSTN lines.


The digital VoIP gateway is useful when connecting the VoIP phone system to digital voice lines. In addition, it connects the traditional PBX system to the existing IP network.

The main distinction between the two types of VoIP Gateways lies in the interface that each possesses for attaching to various components in the network.

Features to Look for in Choosing Best VoIP Gateways Options

  • Compliance with VoIP protocols such as SCCP, H.323, and SIP
  • Echo cancellation for increased audio quality
  • Administrative method i.e. web-based or remote controlled
  • Least Call Routing (LCR) capabilities for cost savings
  • Codecs supported to optimise bandwidth and sound quality
  • T.38 compliance if you intend to use a faxing machine
  • Jitter buffer for stable calls