First Looks: Digium’s Sexy Little IAXy

The folks behind the Asterisk open source telephony software will soon release a telephone adaptor that uses the IAX protocol, and (gasp) forgoes SIP. Here's an early look at what is sure to be a big hit among Asterisk users.

By now, most internet telephony users are familiar with that common piece of VoIP hardware, the mighty ATA (Analog Telephone Adapter). Komodo (later bought by Cisco) started the idea. Sipura Technology, with its SPA-2000, refined both form and function. Now Digium is weighing in with its take on the concept: IAXy.

The IAXy (pronounced "eek-see") is a single-port Ethernet to Telephone adapter designed for use with Asterisk, Digium's open-source telephony software.

Unlike all other ATA devices to date, IAXy, as its name implies, uses IAX (the Inter Asterisk eXchange protocol), rather than SIP, for its communications on the wire.

IAXy boots against a DHCP server, and is provisioned by a simple command-line tool with configuration data such as: the IP address of the Asterisk server to which it should connect, username and password.

Currently, only the ULAW (G.711) codec is supported, although ADPCM will be supported in future through a firmware update.

Roughly the size of that ubiquitous tin of mints found at newsstands and convenience stores everywhere, IAXy is perhaps the smallest ATA around.

A glance at the interior reveals that Digium has in fact built the unit around the FXS daughtercard from their own TDM400. The interface panel consists of: RJ-11 modular jack; recessed reset button; RJ-45 ethernet port; 9V DC jack.

The current limited-release models are not shipping with a power adapter, though Radio Shack part numbers 273-1771 (9V 1500mA) or 273-1715 (type "L" adaptaplug) will work. Digium is constructing power adapters to be included with the full-release version.

The price of IAXy is expected to be comparable to that of the Sipura SPA-2000.