The phones themselves, which look like typical IP screen phones, embody all the switching, auto attendant, directory, transferring and voice mail features usually run off the central PBX, whether IP or traditional TDM.

Marc Gingras, Nimcat's vice president of business development, manned the Nimcat booth at the VON show Wednesday, demonstrating how a Nimcat-running IP phone, when plugged into the LAN, simply asks for an IP address and a user name for the directory. When more phones are similarly added to the network, they discover each other.

They also back each other up. Voice mail left for a disconnected phone is stored by a neighboring phone, retrievable through that phone or remotely. When the phone is reconnected, it quickly downloads its mail from the networked neighbor.

The only other piece of equipment in this system is a small PSTN interface box, to be thought of as a "reverse terminal adapter," said Gingras. With Ethernet and PSTN ports, it simply translates the SIP voice stream back to TDM for exit to the PSTN.

A teleworker with a Nimcat-running phone plugs in with his broadband connection (NATs are no problem, said Gingras), adds IP address, user name, and password, and NIMCat's software creates a "lite" VPN that tunnels back to the home office. The phone gets the next incremental extension number (this can be changed through the system's Web interface), and the teleworker is now an extension on the PBX-less network.

A branch office can also be networked into the system through a Nim Tunnel, and can also use a pre-existing VPN (virtual private network) router for a more robust VPN solution.

The phones do 120 PBX features, including small-scale conferencing. Each phone can conference in two others. Groups of up to four can meet on cascaded phone bridges before the voice quality suffers, Gingras said. The Web server built in gives everyone Web-accessible access to call-forwarding features, call logs, extension-number assignment, voice mail as e-mail attachments, speed dials—features we've come to know through the IP PBX vendors and IP Centrex services.

The phones running Nimcat software will be first brought to market by Aastra, sometime in the first quarter of 2005. Because they're SIP-compliant, they should work with SIP proxy servers on service provider networks, to realize further VOIP (voice over IP) economies in dialing outside the company network. This will take some software accommodation with these providers, however, and carrier agreements are in the investigation stage.

Gingras said that the Nimcat solution should have great appeal to businesses of around 75 employees and fewer; it addresses the "pain point" of those who'd rather not pay the $700 to $1,400 per user it costs to equip an office with PBX and extension.

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