How Does A VoIP Adapter Work?

Posted on: 2015-10-14 | Categories:VoIP VoIP Phones VoIP Services VoIP Technology

Now that VoIP (read article: What is VoIP?) has been firmly established as the communication standard of the future, consumers and businesses are switching over from conventional landlines en masse.

The technology and the terms associated with it are no longer technical jargon or buzzwords known only to a few. A lot more people are aware of how to use VoIP phones and their myriad features.

Nonetheless not everyone knows all the various devices that go into a successful VoIP deployment.

VoIP is very flexible and allows users several alternatives for making calls – from a computer, an IP or desk phone, an application on a mobile device or even a conventional telephone instrument that works on POTS.

The last part is what surprises most people since they don’t expect their current instrument to work with new technology.

Why do you need a VoIP ATA?

However, you cannot simply plug the instrument into the router (or computer) to make it work. This is because landlines are not equipped with the hardware to translate voice signals into digital packets that can be transmitted through the Internet.

In order to use the analog phone with VoIP, users need an intermediary device – the Analog Telephone Adapter (ATA).

The device may be called different names by various manufacturers but its essential function is the same – convert voice signal into data packets, authenticate the instrument on the VoIP service, provide dial tone, interpret touch tones etc.

What does it look like?

An ATA device usually consists of a small enclosure with multiple ports (to provide connections to the landline and the router) as well as a power source.

The ATA may have one or more ethernet ports which allow the device to be connected to the router for Internet access. Similarly the device will have one or more FXS (Foreign Exchange Station) ports which are used to plug-in the landline instrument.

Some adapters also come with FXO ports (Foreign Exchange Office) which can connect a POTS line to the device and is often used as a failover or lifeline (in case the Internet/VoIP service goes down).

Types of VoIP Adapters

Single FXS – As the name implies, these adapters come with a single FXS port that can connect one landline to the VoIP service.

Dual FXS – These are slightly more expensive adapters that offer dual FXS ports for users who want to connect to instruments or one instrument and a fax machine.

FXS/FXO – These adapters include both FXS and FXO ports that can be used to connect analog landline instruments as well as landline connections.

They are most commonly used by enterprises that want to retain landline access as a failsafe or to be used in case of emergencies. The adapters are also especially useful if the VoIP vendor does not support digital faxing but the enterprise still needs to send the occasional fax.

Organizations that need to connect more than a handful of lines or instruments to the VoIP network will need to use a VoIP gateway. These gateways function just like adapters but they are built to scale and come equipped with up to 48 ports in some instances.

How to choose an ATA to purchase?

There are a lot of alternatives available on the market but the number of ethernet, FXS and FXO will determine how many instruments can be connected through one ATA device.

For the average consumer, a simple ATA with one ethernet and one (or two) FXS ports is generally sufficient. More often than not, the VoIP vendor will generally provide the ATA if the customer signs up a contract. However, if you leave the service before the contract expires, you may be liable to pay termination fees.

Businesses on the other hand have several considerations to keep in mind. Depending on the sophistication of the device, the price can range from $20 all the way up to $100.

Although cost is generally not the deciding factor when it comes to purchasing adapters, the business should be prepared to include the cost in the budget – especially if they have more than a handful of employees.

Enterprises will want to consider how many lines they need to connect, the availability of ethernet ports, the need for sending faxes as well as compatibility with the VoIP service before purchasing any device.

How does the VoIP adapter work?

ATAs are generally very simple devices whose most basic function is to convert the human voice into data packets and vice versa.

Using an adapter removes the need for purchasing a new instrument that is compatible with VoIP technology. Ancillary functions include providing caller ID, the dial tone, recognizing touchstones and all the other signaling functions required for a VoIP call.

The ATA works with a specific VoIP protocol and audio codec to to perform its functions. The VoIP protocol is used to communicate with the remote web server and the codec performs the function of converting audio signals to and from digital data.

Protocols and codecs are rarely of interest to the average consumer as their VoIP vendor will provide one for them or offer a selection on their website that are known to work on that particular service.

Business users will need to know what protocol is supported by their provider and the particular audio codecs used will determine the quality of the calls as well as how much bandwidth each call requires.

The most commonly used protocol is SIP – Session Initiation Protocol and it is supported by the vast majority of service providers. A few of the widely implemented audio codecs include G.711, G.729 and many more.

If the adapter was included in the purchase price by the VoIP vendor, they are often preconfigured with the correct settings. If they were purchased separately, the web configuration can be accessed through a computer.

Most enterprise ready adapters are equipped with automatic provisioning so that hundreds of these devices can be deployed at once without individual configuration.

Most businesses and consumers will not use VoIP adapters, instead they may purchase IP phones or use their computer/vendor-provided device to make calls.

But they still serve a useful function for those who cannot afford to buy new IP hardware or have working instruments that have not yet reached the end of life.