The Fruits of my Labour

For those of you who are just joining us, many VoIP users use a piece of hardware known as an Analog Telephone Adapter or ATA.  It allows you to use any analog telephone or legacy PBX and route your calls over the Internet using VoIP.  ATAs made by Linksys are the most popular, probably because of their wide range of configuration options.  They can be configured to match almost any region.  They include the PAP2T, SPA-2102, and SPA-3102.  Let's talk about the technical differences between these ATAs, give you some suggestions about where you can buy them, and most importantly, tell you how you can detect a counterfeit ATA.

Is your ATA locked?

Is your Linksys or Sipura ATA locked to your former VoIP provider?  Why not have your ATA permanently unlocked so that it may be safely factory reset, and may be used with any provider you like?  Contact DogFace05 for more information.

Need to purchase an ATA or other piece of VoIP hardware?

There are plenty of retailers around.  Canadians may wish to use Shopbot.ca to find the best price at a Canadian retailer.  Americans may use Froogle or similar.  Does a deal sound too good to be true?  Maybe it is.  Be sure to check the retailer out on a site such as ResellerRatings.com.  If you don't feel like buying from a particular retailer, reputable retailers such as Netlink Computers/NCIX will often price match in stock items from other online retailers.  If you don't require a new unit, you can often find VoIP hardware on Craigslist.  Be sure to test these items before purchasing.  Sometimes, hardware is locked to a specific provider.  Unfortunately, there are a great deal of counterfeit VoIP devices on eBay (many from Asia) and via 3rd-party sellers on Amazon.  We suggest not buying from overseas and ensuring that your seller has a return policy.

For some information about how to detect counterfeit VoIP hardware, check out this post at DSLReports.com.

Why buy an ATA?  Won't my VoIP provider supply it?

Some VoIP providers require you to Bring Your Own Device (BYOD) while with others, the Device Is Supplied by the COmpany (DISCO).  If the ATA is supplied to you by the provider, you typically need not worry about configuring it as that will be done for you.  If the provider you choose requires you to BYOD, you will need to select and learn how to use an ATA.

Which ATA should I buy?

PAP2T - This is the least expensive of Cisco's ATAs and by far the most popular.  It is an excellent choice for someone wanting to save some money and invest a little time rolling their own phone system, or even a VoIP veteran.  The PAP2T handles up to two providers on two separate lines.  That is, in order to use a second provider, you must have a second phone, or a 2-line phone.  The PAP2T does not support T.38 for faxing.  This means that while it is theoretically possible to send or receive a fax with a PAP2T, it will be slow and will not be reliable.

SPA-2102 - The SPA-2102 is a PAP2T with a few extra features.  It supports T.38, so it will be much more reliable than a PAP2T for faxing.  The SPA-2102 has a built-in router, but not a particularly good one.  Its QoS routing works for some users, however it's not particularly configurable and if it doesn't work for you there's very little you can do to fix it.  If you don't have a router that supports Quality of Service to prioritize VoIP, the best, most popular, and often cheapest option is any router with Tomato firmware installed on it.  A good QoS router is very important so that regular internet traffic does not degrade the quality of your VoIP calls.  With QoS, you can make VoIP calls with audo quality indistinguishable from (or better than!) POTS.

SPA-3102 - The SPA-3102 handles multiple providers in different ways from the PAP2T and the SPA-2102.  It only has one line so you can only make/receive one call at a time, but you can use the same phone and route the call through any provider you like using its gateway feature.  It does have an FXO port for connecting a POTS line.  The thought behind this feature was that you could call its POTS line from some other location and route your call inexpensively out over VoIP.  Or, you could route local calls through the POTS line and long distance through VoIP.  Unfortunately, the FXO port does not work nearly as well as many users hoped.  Most report poor audio quality including echoing.  The SPA-3102 supports T.38 and contains a similar router to the SPA-2102.

OBi100 / OBi110 - Well...these aren't Linksys devices, but they were designed by the same engineers that designed the above-mentioned Linksys devices, so we felt it prudent to edit this post with the following information: The primary reason to select one of these devices is for their support of Google Voice.  They support two service providers, either or both of which can be Google or some other SIP provider.  They offer neither a router nor T.38.  The OBi110 has an FXO port and we are very eager to know if this FXO port performs any better than the one in the SPA-3102.  If you've tested one, please leave a comment below and let us know.

How should I configure my ATA?

We're glad you asked.  Check out our article on Configuring a Linksys VoIP ATA.


You may also want to consider an IP phone.  While IP phones typically involve a larger financial investment than an ATA, they often have more/better features.