What is a VoIP Gateway?
VoIP technology’s roots can be traced to the first Internet-based phone calls. Since then, the technology has progressed further than ever imaginable at the time. Better security, reliability and redundancy have made modern VoIP the number one choice for business telephony.
Despite the advantages of VoIP, analog and digital telephony still has its place in many businesses. While VoIP offers a great return on investment, especially for monthly phone bills, migrating fully to VoIP isn’t always cost-effective or efficient.
VoIP gateways can be deployed to interface analog or digital telephony with VoIP resources. For example, connecting a legacy phone system to an IP network or VoIP service. A gateway can also connect analog or T1 lines to a VoIP system.
Scenarios to Deploy a VoIP Gateway
A VoIP gateway is necessary if there are analog or digital phones systems or lines that need to be converted to IP-based telephony.
Rather than migrating to a full VoIP solution, many businesses choose to keep some legacy equipment (analog or digital). A VoIP gateway lets the business migrate to IP-based telephony in stages, which may be more affordable than a complete overhaul of the network. The business can purchase a VoIP phone system or sign up for SIP-based service, while keeping the existing analog phones and fax machines.
A pervasive myth about VoIP is that it loses service easily. VoIP relies on an Internet service provider; if the service goes down, then so does the phone system. For this reason, businesses will keep a few analog lines connected as a failover system. Should the primary IP PBX go offline because of the ISP, maintenance or any other reason, the failover can use the analog lines to make calls. Certain gateways support this desirable capability.
Having a VoIP phone system on site lets employees make intercompany calls without being routed to the PSTN first. A company that infrequently makes outside calls, but many internal calls, may choose to keep their PSTN and interface it with a VoIP phone system. The gateway can perform this interface function.
What about keeping the legacy phone system? Sure, that’s definitely possible with a VoIP gateway. The gateway can let the PBX access VoIP resources. Combine the system with IP-based features like unified communications for messaging, email and video conferencing.
Analog is one of the oldest forms of modern communication. It is based on analog signaling, which uses the voltage of the line to produce audio. Sound waves and line voltage work together to create what we call analog signaling. It’s an ingenious idea that’s still heavily in use in paging equipment and other sound systems.
The problem is that analog signals can easily lose quality. Television static is the result of “noise” getting in the way of the analog signal. Analog telephony is subject to that same problem.
Analog is barely comparable to VoIP technology. VoIP allows wideband or high-definition audio transmissions for more natural sound reproduction. It also allows more information to be passed between the two ends of a call because the audio is being transmitted over an IP-based signal—VoIP literally means, “Voice over IP.”
The standards for digital telephony vary across different parts of the world. In North America, Japan and South Korea, T1 is the standard for digital transmissions. In Europe, E1 is the standard. For the purposes of IP Phone Warehouse’s customers, we’ll only look at T1 digital telephony.
T1 telephony uses either a copper wire or fiber optic cable to connect the business’ phone system to the service provider or carrier. A single T1 line can support 24 simultaneous calls or about 60-times more data than a traditional analog modem.
The world-famous Bell Labs created DS1 or Digital Signal 1. DS1 defines how data is transmitted over the T1 line. A DS1 circuit supports full duplex or concurrent back-and-forth transmissions, which is incredibly important to telephony. Up to 24 channels are supported by the standard.
Technical details aside, T1 was a revolution when it was first introduced. No more using a single analog line to support each phone. An enterprise’s phone system looked like, for lack of a better word, a huge mess when analog was the standard. T1 allowed the lines to condense and be more manageable.
The voice quality in T1 is not as great as it is for VoIP. T1 is also much more expensive than VoIP telephony or SIP trunks. For these reasons and more, businesses with T1 are migrating to VoIP.
Several VoIP gateways support T1 spans, letting the business interface T1 lines or a digital phone system with a VoIP phone system or IP network. Fully migrating to VoIP may not be entirely cost-effective to the business, or having T1 lines available may be necessary if the primary IP PBX is down.
Session Border Controllers
A special breed of VoIP gateways are called sessions border controllers, or SBC appliances. SBCs are popular with service providers and enterprises as they often include an additional layer of security. They should not be used in place of a firewall; instead, they provide a more distinct boundary between the network and outside environments.
“Session” refers to the call or interaction, “border” refers to the end of the network topology and “controller” refers to the administration of the appliance’s roles.
The reason that SBCs are deployed more often with service providers and enterprises is because they offer a more secure entry point to the VoIP network. Networks in service providers and enterprises receive more traffic and are subject to more malicious activity than a small business or home office.
The best way to troubleshoot your VoIP gateway is to contact IP Phone Warehouse. We offer comprehensive technical support services to help you solve compatibility issues, audio problems, network difficulties and more.
IP Phone Warehouse staffs certified engineers and technicians that understand the ins and outs of VoIP gateways and IP equipment. Our technical support specialists boast at least five years of experience each. No number games here! Only quality support.
IP Phone Warehouse can also assist with firmware updates and questions about your warranty.
For additional help, we recommend looking at the manufacturer’s website. The manufacturer will likely have an online portal to access help tools, FAQ and knowledge base articles.
Purchasing the Gateway
Browse our full catalog of VoIP gateways. We offer a large selection of gateways with varying interfaces and features, specialized for a number of different deployment types.
Questions? Contact our pre-sales tech support channel before you order. We’ll double check that the product you want to purchase is the right fit for your network and VoIP environment.
For VoIP service providers, contact us about provisioning programs and hardware fulfillment. Get your end users the products they want at an unbeatable price, and leverage our technical support too.
We also sell a number of VoIP gateways and session border controllers that are built to support your hosted VoIP service. All ends of your business will be fully supported by IP Phone Warehouse, which is an authorized and certified VoIP gateway reseller.
For Other Deployments…
Smaller deployments may only require an analog telephone adapter or ATA. An ATA usually offers one to four FXS ports, and might include an FXO port for PSTN failover too. Set them up on a desktop, plug in the devices and the network, and go!
A specialized PCI or PCI Express card with analog or T1 cards can also interface legacy equipment or connections with a VoIP network. The cards can be stacked in a server and replaced as need be. Some cards are modular, letting you exchange the ports on the card. This solution can be more flexible than a gateway, but might not offer the same amount of dedicated power or security.
What Does an ATA or VoIP Adapter Do?
Analog phone lines once ruled the world. Submerged telegraph lines crossed oceans and connected distant lands. Then, the telephone sparked the creation of exchanges and phone systems.
Today, the technology behind these marvels is outdated. Manufacturers rarely apply new features to analog phone technology. VoIP is becoming the standard because of its greater return on investment and feature set.
The problem with transitioning to VoIP is that a lot of businesses still have their analog equipment. The two technologies are drastically different. Replacing analog devices with IP devices can be incredibly expensive, or a business may not want to get rid of their battle-proven office equipment.
Analog telephone adapters are the solution for interfacing a couple of analog devices with a VoIP service or phone system. An analog telephone adapter, or ATA, typically features up to four FXS ports for connecting to phones, fax machines or modems, plus an Ethernet port for connecting to the IP PBX or VoIP service.
Need some quick suggestions? Here are five of our customers’ favorite ATAs:
Ports on the Adapters
FXS ports link to analog phones, fax machines and legacy equipment. FXS ports, or Foreign eXchange Subscriber ports, interface with the FXO ports on the back of the analog devices.
An RJ45, Ethernet or WAN port (there are a few names for it) connects the ATA to your VoIP service. The basic ATA features FXS ports and a single RJ45 port.
Rather than cancelling the connection to the PSTN or analog telephone service, a lot of businesses like to keep this subscription. An analog telephone adapter with an FXO port can connect to the PSTN. The FXO port can provide a failover telephone line should the primary VoIP service become disconnected.
Some ATAs feature built-in routers, meaning that in addition to the WAN port it also includes a LAN port. The LAN port connects the adapter to a local network.
USB ports provide analog telephone adapters with links to storage devices, firmware updates or anything else that the ATA can support.
Protocols, Codecs & Audio Quality
VoIP relies on protocols. A protocol tells end points and services how to signal each other. A protocol is similar to how humans use language to communicate. Two people with dissimilar languages will have a very hard time communicating, and the same holds true for VoIP end points and services.
SIP is an incredibly popular protocol that’s becoming the standard for VoIP telephony. When VoIP was first developed, manufacturers created their own protocols, which resulted in a lot of incompatibility between VoIP services and devices. Having a standard protocol benefits both users and manufacturers. The open source SIP protocol is quickly turning into that standard.
Voice quality is generally determined by codecs and audio enhancement technology. ATAs may support wideband and/or narrowband codecs, and enhancements like digital signal processing (DSP) and echo cancellation.
Wideband audio codecs provide the best voice quality possible. Wideband is sometimes referred to as HD voice because it can produce true-to-life sounds and natural conversations. Narrowband audio codecs are preferred in networks that have limited bandwidth.
Digital signal processing can improve telephony or music playback by intelligently enhancing speech and audio. It can also provide echo cancellation, background noise suppression and other tools to cleanup sound performance.
Fax over IP
A VoIP phone can be dialed by finding its IP address. An IP address is assigned to any device connected to a network or the Internet, giving the device a recognizable label. Analog fax machines can also be assigned IP addresses when they are connected to an ATA. The technology is referred to as “Fax over IP” (VoIP = “Voice over IP).
Traditionally, sending a fax requires dialing the receiving machine’s telephone number. The fax is stored and then transmitted over the analog line. Analog telephone adapters that support the T.38 protocol can provide real-time faxing, letting messages be sent and receive instantly. Computers can also send faxes through the T.38 protocol by dialing the machine’s IP address, which greatly increases productivity.
Certain ATAs can do more than connect an analog phone or fax machine to a VoIP phone system. They can also connect your existing analog paging system to the IP PBX. With this setup, pick up the handset on your VoIP phone to issue an alert or notification across the paging system.
The page will go from the VoIP solution, to the ATA, to the telephone adapter module (if applicable), and finally to the analog paging system.
In order for this setup to work correctly, the analog telephone adapter should support calling party control, also known as CPC disconnect. Calling party control tells the paging system that the end user has hung up the handset or microphone. A telephone adapter module may be necessary to interpret the signal from the ATA.
Calling party control is explained in more detail in our blog post:
Hang Up with Calling Party Control.
Shopping for an ATA or VoIP Adapter
IP Phone Warehouse staffs a vender certified sales support team. Contact us for shopping assistance, including finding the right analog telephone adapter or VoIP adapter for your current setup. Our experienced team can pair your phones and services with a compatible ATA, ensuring you get the best experience possible out of your telephony solutions.
Our technicians and engineers have five years of experience. If our sales team cannot find an immediate answer, they know someone who can.
An ATA can provide a return on investment by letting you keep your existing analog phones while migrating your phone system to VoIP. An analog phone cannot support as many features as a VoIP phone, but it is an excellent secondary solution.
Knowledge & Technical Support
Read the articles in
The Dock to learn more about ATAs. Articles include:
"How to Connect Remote Employees with an ATA"
“Bogged Down by Analog? Meet the ATA”
• And more!
Discover the full range of what analog telephone adapters and VoIP adapters can do. An ATA can be more than just an interface between your analog phone and an IP PBX.
IP Phone Warehouse also offers buyer’s guides. Print these documents for future reference when shopping for ATAs.
Need a more personal touch? Contact our free pre-sales tech support. We’ll help you understand the basics when shopping for ATAs and VoIP adapters.
Analog telephone adapters that support web-based user interfaces are easy to manage. Open a web browser to access the ATA, and provision and configure its settings. Maximize performance and boost voice quality by simply tweaking a few settings.
Some VoIP adapters also support firewall and security technology. Keep your telephony secure from eavesdroppers or service attacks.
ATAs for VoIP Providers
If you purchased an analog telephone adapter or VoIP adapter from a VoIP service provider, it might be impossible to change any settings on the device. Sometimes, service providers will lock the user out of the user interface. The reason for this is because the ATA has been provisioned to work exclusively with that service. Cellular service providers do the same thing with cell phones that they issue to customers.
To ensure that an analog telephone adapter or VoIP adapter available on IP Phone Warehouse is compatible with your VoIP service, contact our free pre-sales tech support. We’ll cross reference the device or let you know what adapters are available to your specific service.
If you are a VoIP service provider, check out our
programs for VoIP providers. We can provision ATAs and ship them directly to your end users.
Brands & Configurations
ATAs are available in one-FXS, two-FXS and four-FXS models, plus models with FXO ports to connect to a PSTN or other source. Most are ready for SIP and T.38 protocols for standard-based VoIP and faxing support.
A number of brands are available, including:
AudioCodes builds ATAs in a number of different configurations. They also manufacture rack-mountable VoIP gateways with dozens of ports for larger deployments.
Cisco SPA112 and Cisco SPA122 ATAs are incredibly popular. These ATAs feature two FXS ports, with the latter model offering a built-in router. The ease of use and large feature set makes them highly suitable for most telephony environments.
Obihai ATAs can connect to applications like Google Voice. Google Voice lets you conveniently manage your phones. It is not a phone service, but a way to leverage your existing telephony with a powerful management application.
Another unique analog telephone adapter is the
Patton SmartNode M-ATA. This adapter is incredibly compact. Use this device to interface a single analog phone or fax machine with SIP-based telephony or T.38 faxing.
What is the Best ATA or VoIP Adapter?
From a distance, it looks like all ATAs and VoIP adapters do the same thing. Up close, they are a lot different. Here is a roundup of our customers’ favorite analog telephone adapters based on prices, reviews and features.
Receive the benefits of VoIP without losing your analog phones or fax machines. The Cisco SPA112 uses advanced QoS, SIP and other essential standards to produce high-quality voice. The ATA also supports simultaneous voice and data use, ideal for fax machines. Two FXS ports and a single Ethernet port are available.
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Keep your analog desk phones, conference phones and fax machines with the Cisco SPA122 ATA. The adapter has a built-in router with WAN and LAN Ethernet ports. Both FXS ports on the device have their own dedicated number, and both voice and data services can be running simultaneously.
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High-end features like T.38 fax relay and echo cancellation, without the high-end price tag, give the AudioCodes MP-202 one of the best feature sets available for an affordable ATA. Easily integrate the adapter with VoIP networks, analog devices and your business’ telephony.
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Patton SmartNode M-ATA
The Patton SmartNode M-ATA (micro-ATA) is branded as “the world’s smallest analog telephone adapter.” It brings big VoIP gateway functions to an ultra-miniature form factor. Connect a single analog device to your VoIP network or IP PBX with this space-saving adapter.
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Strong security protection and advanced telephony features equip the Grandstream HT702 ATA for a variety of uses. Deploy it with analog phones or fax machines, ready for small businesses that rely on a number of different VoIP features to fully serve their employees’ telephony requirements.
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