Design
VoIP ATAs (Analog Telephone Adaptors) with custom VoIP branding are nothing new at all; we've seen plenty of them here at CNET.com.au -- products such as the distinctive looking Freshtel 3010 come to mind. The SPA2100 is a Linksys ATA, but in the case of the model we've reviewed, it's arguably a MyNetFone Linksys ATA. Actually, if we wanted to get picky, it's a MyNetFone Cisco Linksys Sipura SPA2100 -- Linksys owns Sipura and is itself owned by Cisco, but the MyNetFone (who don't own any networking companies, in case you were getting confused) lock on the SPA2100, along with lots of branding on the external packaging makes this particular model of interest only to anyone who either is or wants to be a MyNetFone customer. A quick bit of online research reveals vendors selling what appears to be unlocked SPA2100s -- more on this later.

Features
The SPA2100 is a two port VoIP ATA with an additional Ethernet port -- in effect, it's a passthrough port, as the ATA itself requires an Ethernet connection to your home router. Stylistically, it follows the look of older Linksys products, which tend towards more of an enterprise rather than soft and cuddly "home" look. Which is, in essence, the nice way of saying it's a silver plastic box that looks like it belongs cabled to a desktop PC, and not in the middle of the coffee table next to the fruit. While we're normally a little averse about getting into wish list territory, it is annoying that the SPA2100 lacks a dedicated FXO passthrough port -- this would allow you to utilise your normal phone line with your VoIP phone if your broadband connection is otherwise unavailable.

Performance
Set-up of the SPA2100 is remarkably simple, but then it's an ATA -- these should never be difficult to set up in the first place. As long as you've got a working router with DHCP enabled, they should at worst be a matter of setting a few key fields within the ATA itself. One nice aspect of the SPA2100 is that this can be performed either from within a router-style Web interface, or using a phone keypad, although you'll need a bit of patience for this latter approach to work.

Once we'd set up the SPA2100, we tested its phone quality. Obviously this will vary depending on the quality of your broadband connection, and what else it's being called upon to do. Call quality was good for our purposes when testing, and we were impressed that the SPA2100 maintained its connection over a number of days. We've tested plenty of ATAs previously that have required nudging-style reboots every couple of days to maintain themselves, and had no problems of this sort with the SPA2100.

As many VoIP providers do, MyNetFone has locked down the SPA2100 to work only on its systems, and only with the account it's first registered with. We can't fault them for following normal industry practice per se, but we were still annoyed with the SPA2100, simply because of the limitation of the interface that means it's not within the user's grasp to even change between MyNetFone accounts by themselves. This can be done -- but you've got to contact MyNetFone support in order to do this, rather than being able to change key fields yourself.

Given that the price difference between the locked SPA2100 (AU$89 via MyNetfone with AU$5 worth of call credit provided, although we did find online vendors selling the MyNetFone model for as much as $20 less) and what appear to be unlocked models -- around AU$130 -- it may be one ATA that's worth buying unlocked if you suspect you may want to change VoIP providers in the future.