What Is a VoIP Gateway? Definition & How to Use It

Voice-over-internet-protocol (VoIP) systems won’t work with older, traditional office phones unless you use a device known as a VoIP gateway or an analog telephone adapter (ATA). This is because older phones rely on analog technology to make or receive calls, while VoIP uses digital technology. VoIP gateways bridge this gap by converting analog signals into data packets, which can then be transmitted over the internet.

Read on to learn more about what VoIP gateways are, how they function, available types and brands, and its benefits to your organization.

How a VoIP Gateway Works

VoIP gateways work internally by first determining where the traffic originates from (like a VoIP softphone or analog device). It then determines where it’s going—an internet-protocol (IP) or public switched telephone network (PSTN) and turns the data into the appropriate format.

Externally, VoIP gateways connect analog and digital networks and devices using a phone jack, also known as a register jack-11 (RJ11). The register jack-11 then plugs into your VoIP gateway’s foreign exchange office (FXO) or foreign exchange subscriber (FXS). The gateway may also have an Ethernet port for connecting to your internet service.

Once the VoIP gateway is connected, the device then enables your existing hardware, such as desk phones and fax machines, to communicate with either PSTN or VoIP services. Your staff can also answer multiple phone lines on different networks without switching devices. Depending on the hardware, your gateway may work with several network types, such as:

Cloud-based and on-premise public branch exchange (PBX)
Integrated services digital network (ISDN)
Local area network (LAN)
Time-division multiplexing (TDM)
Global system for mobiles (GSM)
Code division multiple access (CDMA)
Plain old telephone service (POTS)

VoIP gateways are an excellent option for businesses wanting to switch some or all of their communications to VoIP—especially for those companies that don’t want to purchase analog telephone adapters (ATAs) for each individual device.

Types of VoIP Gateways

VoIP gateways have different capabilities. Analog gateways let you connect your conventional equipment to your VoIP phone system (FXS gateway) or send IP-based communications to your PSTN (FXO gateway). VoIP gateways may have one or both types of connections. Digital gateways support E1/T1 (ISDN) lines and serve as a bridge between legacy PBX and your IP network.

Here are the three types of gateways:

FXS gateway: Foreign exchange subscriber ports link analog devices or on-site PBX systems to internet-based phone services.
FXO gateway: Foreign exchange office ports connect your landlines to cloud-based PBX phone systems, VoIP phones, and analog devices.
Digital VoIP gateway: This port connects digital lines, such as an ISDN or primary rate interface (PRI) circuits, to your VoIP phone system.

When choosing a VoIP gateway, think about how many concurrent calls your device should support and how many FXS and FXO ports you need. Typically, low-density hardware has fewer ports than high-density models, making them a better option for smaller offices. Analog gateways offer four, eight, 16, 24, or 48 ports, whereas digital consoles have one, two, or four E1, T1, or basic rate interface (BRI) slots.

Also, make sure it’s interoperable with your VoIP and landline carriers. Although most gateways support session initiation protocol (SIP) standards, vendors often provide a list of preferred hardware. Their technical service teams are likely familiar with these models and are able to offer better assistance than troubleshooting an unknown gateway. You can also check out our guide to setting up a VoIP system to plan for a smooth transition to VoIP services.

VoIP Gateway Benefits

Now that we’ve answered the question of what is a VoIP gateway, it’s time to dive into why companies use them. The best VoIP phone services provide many features that improve communication, including schedule-based routing and business texting. VoIP gateways let you take advantage of these features without overhauling your current infrastructure and equipment.

Supports Hybrid Phone Systems

VoIP statistics show that information technology (IT) professionals and business owners are shifting to internet-based phone services at rates potentially higher than those choosing landlines. According to Blueface’s Business Communications Technology report, “35% of all businesses surveyed now have a business VoIP line,” and “61% have resolved to switch” to IP-based calling.

However, many organizations don’t roll out VoIP services to all employees and branches at once. There are several reasons for this, including reliability concerns and legacy infrastructure investments. A VoIP gateway with FXO and FXS ports works with both types of lines and devices. It allows you to continue using existing equipment while meeting digital transformation goals and retaining a landline for emergency failover.

Reduces Total Cost of Ownership (TCO)

Installing a VoIP phone system can be free if everyone uses a softphone application on their computers, tablets, or cell phones. Indeed, Telzio finds that “companies can reduce monthly telecom costs by over 50% by switching to VoIP.” But, your initial expenses will increase if you need to purchase all new IP phones or individual ATA adapters for each device.

In this case, a VoIP gateway can reduce your costs as it supports your existing devices. One low-density gateway is often cheaper than buying a dozen adapters for a small office. You can also decrease your monthly long-distance bill. Employees who frequently call customers worldwide can use VoIP services like GoTo Connect or 8×8 to make unlimited international calls over the internet.

Ensures Business Continuity

An unplanned network or power outage can bring your company to a standstill. And when your business phone system needs the internet, downtime means you can’t answer customer service calls or accept payments over the phone. Fortunately, you can forward calls to mobile devices when using services like RingCentral and Nextiva. Vendors also offer automatic failover routing, routing calls to predetermined phone numbers during an outage.

Many companies simply can’t afford the risk. These include businesses providing emergency services and those located in rural or remote locations. They may keep a backup line as a phone system failover in these cases. Some VoIP gateways automatically switch from your IP-PBX to a backup landline if your VoIP system or utilities go down.

Improves Ease of Use & Administration

Although you need some computer networking experience to set up a VoIP gateway, it’s easy to monitor after the initial installation. Most gateway hardware provides browser-based diagnostic, setup, and monitoring tools. In addition, if you choose a model supported by your VoIP provider, they can help troubleshoot problems and pre-provision the console, so it’s configured when you receive it.

Add new phones or lines by simply plugging them into your gateway or connecting them to your IP PBX system. As long as you have enough ports and support for concurrent calls, you won’t need to purchase or configure your equipment every time you scale up or down. Plus, your staff can keep using devices they’re familiar with instead of switching to new phones.

Manufacturers to Consider for a VoIP Gateway

VoIP gateway manufacturers offer low- and high-density devices that are compliant with multiple protocols and support several voice codecs. The solutions differ based on the number and type of ports. Remember, you’ll need a VoIP subscription to use a gateway, and it’s a good idea to check with your VoIP provider to ensure compatibility.

Explore devices from well-known brands, such as:

AudioCodes: Analog gateways feature two to 288 ports and fax support, whereas digital gateways support two to 16,000 channels.
Patton: SIP gateways allow faxing and have one to 128 ports. Digital gateways support up to 120 simultaneous faxes or phone calls.
Grandstream: Digital gateways support up to 120 concurrent calls and have an integrated network address translation (NAT) router. Analog gateways have up to 32 ports. Both types support faxing.
Vega: Digital gateways allow up to 240 simultaneous calls, whereas analog devices provide up to 50 ports. Digital and analog gateways support faxing.

Frequently Asked Questions (FAQs)

Do I need a gateway for VoIP?

No, a VoIP gateway isn’t a requirement for IP-based phone services. Instead, you can download a softphone application on your computer or mobile phone to make calls over the internet. Alternatively, you can connect an ATA adapter to your analog phones and use them for VoIP calling. But if you want to connect many desk phones, a VoIP gateway may be a less expensive solution.

Can I use a business fax machine with VoIP?

Yes, a conventional fax machine can send faxes over the internet as long as it is connected to the internet via an adapter or VoIP gateway with the T.38 codec. Also, your VoIP subscription must support internet faxing. This feature comes standard on all Nextiva plans and RingCentral’s Standard, Premium, and Ultimate packages.

What is another name for a VoIP gateway?

A VoIP gateway may also be called a SIP gateway, FXO gateway, or FXS gateway. These terms refer to the types of connections available, yet they’re all known as VoIP gateways. An analog telephone adapter (ATA) is a gateway for a single phone, whereas a VoIP gateway connects multiple devices.

Bottom Line

VoIP gateways connect your non-digital hardware—from security systems to fax machines, to your internet-based phone system. This is an affordable way to improve communications without overhauling your current infrastructure.