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Routers Features and Terminology for VoIP Use

AC/AX Router Class

These classifications together with a number appear in the router's name (for example Netgear Nighthawk AC1750) and indicate two things:

  • AC/AX indicates the Wi-Fi networking standard supported by the router. AC is for the 802.11ac (also known as Wi-Fi 5), while AX is for the 802.11ax (also known as Wi-Fi 6).

  • The number following AC/AX denotes the theoretical combined maximum speed for the two or three Wi-Fi networks on dual-band or tri-band routers. The number is usually rounded to make it more readable.

    For example, a dual-band AC1900-class router can offer a maximum speed of 600 Mbps on its 2.4 GHz frequency and 1300 Mbps on its 5 GHz frequency. A tri-band AX4500 router 2.4 GHz band runs at 860 Mbps and its two 5GHz bands run at 1802 Mbps, giving a total of 4464 Mbps that is rounded to 4500 for readability. 

Cellular Network

A cellular network connection on a router allows it to use a SIM card, just like the one found in your smartphone, to connect to a mobile provider for Internet access. If you connect users to this router over Wi-Fi you can have a completely (network) cable-free office environment (however wired connections to the users are still preferable being inherently more stable and secure.)

Some cellular network routers can support two or more SIM cards. This offers a backup cellular service in case of an outage with one of the providers. The SIM cards can also be combined to offer users faster and more reliable Internet access by a bonding or load balancing feature. Bonding is preferable for VoIP.

You may be able to plug a cellular modem in the USB port of a router that doesn't offer a cellular connection natively. But make sure that the USB port and the router support an external cellular modem. 


A Wi-Fi band refers to the operational radio frequencies of a router. A single-band router operates on the 2.4GHz frequency while a dual-band router operates on both the 2.4GHz and the 5GHz frequencies.

A tri-band router hosts one 2.4GHz network and two separate 5GHz networks. Both dual-band and tri-bands routers can automatically split traffic between the different networks to maximize speeds for connected devices. Newer faster Wi-Fi protocols can also operate on 60 GHz frequency and this will enable quad-band routers to become the norm.

The 2.4GHz is the original frequency used for Wi-Fi. It is also used by many other wireless devices, like Bluetooth devices and cordless phones, that can cause possible interferences and degrade performance. Therefore, not only do the 5GHz frequency's shorter radio waves provide faster speeds (up to 2.5 faster than 2.4GHz) but a dual-band or tri-band router can operate on a less crowded frequency to deliver better performance.

Each frequency is divided into different segments called channels (you can think of these as traffic lanes for the frequency.) There are common Wi-Fi tools that can analyze your own and neighboring networks to suggest the least crowded channels that you can select.

While 5GHz also offers more channels, with its growing popularity it is becoming increasingly more crowded. It does also have the disadvantage of covering only a third of the distance and not passing through walls and solid objects as well as the 2.4 GHz.

Generally speaking 2.4GHz does provide sufficient speed for VoIP and will work better for far phones/devices – up to ideally about 150 feet from the router. But if the 2.4GHz is congested (you can test this with a Wi-Fi analysis tool) and the phones are closer to the router (up to 50 feet) you should try to operate your VoIP over the 5GHz frequency. If the phones are further away and you do need to use the 5GHz band, you can install range-extenders or a mesh Wi-Fi system, but do keep in mind that these add latency. Eventually, the choice is about considering and balancing several factors.

Gigabit Ethernet (GbE)

In telecommunication and computing, this is a wired networking technology that delivers a Gigabit (1000MB) per second data transfer rate – ten times faster than regular fast Ethernet.

A Gigabit router provides your telephony network with a faster and more reliable connection.

Note that the current popular Wi-Fi 4 standard typically delivers top speeds of up to 500MB per second. If you connect devices wirelessly to a gigabit router you would only be using half of its potential, but for VoIP this speed is more than sufficient and the newer Wi-Fi standards will surpass gigabit performance. See more about Wi-Fi below.

Also, in some office environments there is a limited amount of available data ports and dual data jacks on SIP phones are used to wire devices to the network. Unless a computer is plugged directly into an Ethernet port, the maximum network speed available to it will depend on the phone’s specification. For example, if you have a one-gigabit network, but your computer is connected to the network via a slower 100 Mbps phone then your computer will only be able to achieve a maximum 100Mbps data rate. 


LAN Ports

LAN stands for Local Area Network. LAN ports are where Ethernet networking cables are plugged in to connect your router locally with other networking equipment and devices (computers, SIP phones, printers, servers, etc.) LAN ports allow devices on the network to share the Internet (which is delivered on the WAN port) and communicate with each other.

Most SIP phones will have two LAN ports. One connects to a network socket while the other connects to a PC. This allows the two devices to share one network socket and makes it much easier to deploy SIP phones. It also allows Telbroad's TeleConsole app to let you receive and control calls on either the phone or the PC.

A basic router usually comes with only four LAN ports but can support more connections using a network switch – a device that splits the network communication among its own LAN ports (switches come in configurations of 5 to 52 LAN ports.)

Number of Devices/Users

While even an entry-level router with standard network configuration can theoretically support up to 255 devices (wired or wireless) in practice an acceptable performance depends on several aspects. 

The router's hardware is the major factor for the manufacturer's number of recommended devices it can handle. The amount of RAM and CPU speed of the router determine how fast it can encrypt and route data packets, resolve network addresses, and handle firewall functions.   

There is a consideration for how often devices are actively using the network simultaneously. An office where users are just occasionally accessing the Internet is unlike a busy call center where all SIP phones are constantly sharing the broadband connection. 

With a Wi-Fi connection, the layout of an office is also important as physical obstructions and electromagnetic interference can further limit the number of useful connections.


QoS stands for Quality of Service. It is a definition of network data delivery efficiency measured using metrics such as packet loss, latency, jitter, congestion, etc. 

In high-quality routers, QoS is a valuable feature that can prioritize certain data packet types or services. While VoIP is not a demanding technology in terms of bandwidth, it is not very forgiving when it comes to latency or jitter. Therefore in VoIP, in particular, enabling QoS and defining VoIP with the highest priority can make an important difference in call quality. 

USB Port

A USB port on a router is not essential but can provide some useful functions. You can use it for connecting and sharing a network printer or a local network storage/backup solution. While these can also be plugged elsewhere on the network, connecting them directly to the router makes them more accessible and easier to set up.  

The USB port is also useful for upgrading the router's firmware or installing custom firmware. You can read more about firmware upgrade/installation here. 

Another function of the USB port is connecting a cellular modem to a router that does not have a built-in cellular component. But note that the USB port needs to specifically support this option!

WAN Port/Multi-WAN

WAN stands for Wide Area Network. A WAN port on a router (or a broadband modem) is where the Internet signal is delivered to from the Internet service provider. Having two (or more) WAN ports gives you the ability to connect to two different Internet service providers simultaneously. 

You can use both ports together to increase reliability and maximize that bandwidth available to users. You can also use one port as your primary service and the other in case of an outage with the first provider.


Wi-Fi is a ubiquitous networking technology that delivers wireless high-speed Internet and network connectivity with the use of radio waves.

Wi-Fi allows for more flexibility in a VoIP setup, making it possible to connect a SIP phone (or a device with a softphone) to a Wi-Fi network even when a network socket is not available or too far. The SIP phone obviously needs to support Wi-Fi. Some models that don't support Wi-Fi natively can be extended to offer Wi-Fi with an additional USB adaptor. Refer to our telephone buying guide for more information. 

Wi-Fi has evolved over the years through various, increasingly faster, protocols. The current common protocol is called 802.11ac and theoretically exceeds gigabit speed. In practice, however, it does not deliver even half of that speed (802.11ax the next generation of Wi-Fi will guarantee to surpass gigabit speed.)

The considerations for a Wi-Fi actual signal speed are distance to the router, physical obstructions, number of users on the network, and radio interferences from other devices or networks. If you are experiencing call quality issues on a phone connected via Wi-Fi while using Bluetooth headsets, consider changing the Wi-Fi frequency or channel on your router.  

While VoIP should work fine over Wi-Fi with the current speeds, a wired Ethernet connection is still preferable being inherently more stable and secure.


WPS stands for Wi-Fi Protected Setup. It is a router feature that lets you connect to it wirelessly without having to enter a Wi-Fi password. Instead, you activate the WPS connection on a device and push the WPS button on the router to make it discoverable for a short duration (usually two minutes). The device and the router will get paired and a Wi-Fi connection established. 

WPS is especially handy for the initial setup of a router before its passwords have been customized. However, when WPS is activated it exposes your router to uninvited connections and is considered less secure than other Wi-Fi authentication protocols.

For this reason, some manufacturers choose not to make WPS available on their business-grade models. If your router does have a WPS it is advised you disable it after the initial router setup or when it is not being used. If you choose not to disable it you should at least ensure the router is placed in a secure location that prevents access to its WPS button. 

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