Software developer Unison has launched what it claimed is the world's first fully-unified communications suite based on Linux.

Announced at CeBIT, the suite (also simply called Unison) combines IP telephony, email and instant messaging with diary, address book and presence capabilities, all in a single Linux server. It is available free as a public beta.

"You can get all these elements separately on Linux, but this is the first time they have all been in one server," said Rurik Bradbury, Unison's chief marketing officer. Other unified communications (UC) schemes, such as Microsoft's Office Communications Server (OCS) can require three or more servers to do the same thing, he added.

"If you're reasonably familiar with Linux, you can deploy Unison in a couple of hours, and have a complete system running for a company of perhaps 50 or 60 people in half a day," he said.

The server software works with a Unison client program for Windows PCs. This provides a genuine alternative to Microsoft's combination of Exchange and Outlook, Bradbury claimed.

"We're amazed no-one has done this before -- build both a client and a server. Others have either one or the other," he said. He added that a Linux version of the client will come later this year.

Unison is aimed at 20- to 300-seat organizations, but the US-based company plans to add server clustering in the future to support more. It is partly based on open source technology, such as Thunderbird for email and Jabber for instant messaging, and partly developed by Unison's own programmers.

The software is initially offered as a free beta version but is already fit for use, Bradbury claimed.

"It is almost finished -- it is relatively stable software," he said, joking that he uses commercial software that's less robust.

Once the beta program is complete there will be a free "community" version for up to 20 users, and per-user or perpetual licences will be sold for larger systems, although pricing for those is not yet fixed.