Sipura Technology, the San Jose, CA-based analog telephone adaptor manufacturer, confirmed in a recent press release a report published in Voxilla last month that Irvine-CA-based Linksys Technologies acquired the rights to use Sipura’s technology in its line of VoIP telephone adaptors.

Two of the three pre-announced Linksys devices – the dual telephone port PAP2 ($59.95 retail) and the wired router/firewall/VoIP combo RT312P ($79.95 retail) – have been available for several weeks from select brick-and-mortar retailers in a package co-branded with VoIP service provider Vonage.

While the bulk of the Linksys devices on the market today are “locked” to the Vonage service and cannot be used with any other provider, a few “unlocked” devices have trickled out in the open market.

We managed to get our hands on an unlocked Linksys PAP2 and put the device to a few tests to compare it with its fraternal twin – the Sipura SPA-2000 ($119.95 retail, $85 street price).

While, to the naked eye, the PAP2 appears to be a little smaller than the SPA-2000, the two devices are actually about the same size. The PAP2 is housed in a plastic 4" x 4" x 1.25" box. The SPA-2000 is 4.5" x 3.75" x 1.5" with a curved case. Both devices have an Ethernet port, two FXS ports, and a power plug. Both use the exact same power supply – a modular 110-240V auto-adjusting adaptor manufactured by Taiwan-based Phihong.

The PAP2 has four blue LEDs in front: one for each phone line, one for the Ethernet connection, and one for power. The SPA-2000 only has two green LEDs: one ethernet activity light and one status light, each on opposite sides of the case.

Beyond the superficial physical difference, the web interface for both the SPA-2000 and PAP2 are also very similar. The PAP2 interface is branded with Linksys information and has a Linksys "look and feel." All of the configuration options on the SPA-2000 are also configurable on the Linksys PAP2.

An analysis of the HTML source code reveals that both devices are programmed in a nearly identical fashion. Even the Interactive Voice Response (IVR) system on both devices sounds identical, except the PAP2's IVR has removed all references to Sipura.

Though very similar, the SPA-2000 and PAP2 use different firmware. It is not possible to load SPA-2000 firmware on the PAP2. At press time, Sipura has version 2.0.10e available for the SPA-2000, which contains a number of bug fixes and minor enhancements. Linksys does not have any firmware available for the PAP2 on its support site, though the PAP2 we have is using version 2.0.10(LSb).

One big difference between the Sipura and Linksys: information about the product on the companies’ respective websites. Linksys does not appear to have a whole lot of information on its website about the PAP2 beyond the documentation that comes in the box. Linksys doesn't appear to have any Knowledge Base articles related to the PAP2. Sipura has a bit more information on their site, including the latest firmware, FAQs, and some configuration information.

The Linksys PAP2 was tested against Stanaphone and Free World Dialup. Both services were configured and functioned exactly as they would with a SPA-2000. The sound quality was clean – as good as from a SPA-2000. There is no reason to believe other service providers that support unlocked SPA-2000s would not work as well with the Linksys PAP2.

The major differences between the Sipura SPA-2000 and Linksys PAP2 is the price and distribution. Based on current street prices, the Sipura SPA-2000 is nearly twice as expensive as the Linksys PAP2. In addition, Sipura products are only available to service providers and through a small number of online retailers. Linksys products are widely available through a number of retail channels.

While Linksys certainly has the means to accelerate VoIP adoption among the masses, they also have the potential to unseat Sipura as the premier manufacturer of VoIP adapters, and to do so using Sipura’s own technology.

Whether or not they do remains to be seen.