Nortel called the launch the biggest since its flagship PBX, the Meridian 1, but what was on show looked a lot like an instant messaging (IM) system. And the announcement was version 2 of a product that has already been available in the US for six months.

At CeBIT in Hannover, and simultaneously in London, Nortel took its previously US-only Multimedia Communications Server (MCS) 5100 worldwide. The product includes a hardware server that links to "virtually any" PBX system, and a software client that shows the online "presence" of co-workers, sets up IP telephony, video, chat, or other communications, and shares content.

It looks a lot like IM, as offered for free by Yahoo!, AOL and MSN, combined with an IP telephony system like Skype or NetMeeting, but connected to a corporate voice network. Nortel says it is the basis for huge savings and productivity gains, with the company itself claiming the product has saved it $28 million on a $6 milllion investment. It has done so, simply by replacing mobile calls with IP telephony and calls out from the corporate PBX.

It's up to date on the protocols required for real-time corporate connection, including SIP, the Session Initiation Protocol, and H.323 for voice and video links. It's exciting enough to prompt BT to sell it, for a one-off cost (bearing some relation to $300 (£163) per user) and to look at turning it into a service as well.

"It's the perfect example of a converged service," said Lucy Dimes, BT's director of ICT and strategic partners, and an evidently delighted member of the 80-person pilot within BT. "It's very intuitive. It just means clicking on icons and I can do that kind of stuff."

Unlike IM, and standalone Internet phone applications, the product can reach out to people on the phone network, through its link to the PBX. But it can be set to take the least-cost or the best function route to get to someone. It currently has around 10,000 users, 5,000 of those within Nortel.

Like any such product, the first response of the journalist is to ask about the things it doesn't do yet, but would be really good. People in BT and Nortel currently use it on laptops, rather than on smartphones - which could send voice over a Bluetooth laptop and bypass the phone network, making it actually as convenient as a mobile.

It doesn't link to other IM systems, yet, and users can't link to the MCS server without a secure link into the corporate network, so it is currently limited in its use for collaboration between companies.

There is clearly a step, or two, to go in integrating it with clients such as Outlook. MCS can import Outlook contact data, and the Outlook client can launch phone calls using it, but it isn't fully integrated in Outlook, like Siemens' rival product, Openscape.

Nortel has a huge video presentation and demo of it here.

The product is being tested at employment site Monster.com, and at the University Hospitals of Geneva (which endearingly abbreviates to HUG in Swiss).