From Mobile Insights

Mobile Letter
Issue XVI - March 17, 1999

Clarinet Systems' EthIR LAN® Infrared-based Wireless LAN

If you're an IT manager for a corporation with personnel scattered around in multiple locations, you not only have to properly equip all your mobile users, you have to make sure that when they come into one of your locations, they can quickly and easily plug into the local LAN. Since we are strong advocates of the concept of keeping things as simple as possible, we were quite fascinated by the possibilities presented by Clarinet Systems' wireless EthIR LAN system, which is specifically intended to interconnect IR-equipped portable computers with the local LAN system.

The EthIR LAN system consists of two components: the EthIR Switch,™ which looks and functions very much like a conventional 10/100BaseT switching hub and a series of IR access sensors which Clarinet has dubbed EthIR Beams®. The EthIR Switch supports both standard Ethernet connectors and the EthIR Beam devices, for which the switch also provides power. This enables seamless integration of handheld and notebook PCs into existing LANs, transforming the network from exclusively wired to "dynamically mobile" in minutes. In addition to supporting Windows 95/98/NT, EthIR LAN is also compatible with Apple PowerBook's and Windows CE handheld computers.

The EthIR Switch is available as a "Dedicated IR Mode" version in 8 port and 16 port configurations and also as a "Pass Through Mode" version with 8 ports and 16 ports. The "Dedicated IR Mode" version supports infrared connections only (via the EthIR Beam). The "Pass Through Mode" version supports both infrared connections (via the EthIR Beam) and 10/100Base-T connections via an Ethernet card. Each user port of the "Pass Through Mode" version needs to connect to an Ethernet hub port to support a wired 10/100Base-T connection.

EthIR Beam, the IR LAN access point, is positioned on the desktop facing the IR port of the portable computer. A dedicated 4Mbps network connection is built automatically when both are within a range of one meter and will terminate when the portable computer is out of range or the power is down.

When the portable computer "connects" to the EthIR Beam it becomes part of the LAN enabling it to access the file server, print, send/receive e-mail, browse the Internet, etc. No additional hardware such as a PCMCIA LAN card or cable is required. Since the EthIR Beam extracts power from the EthIR Switch through its only connection - a twisted pair cable - no additional wires or power adapters are required.

Although the current version of EthIR LAN's 4Mbps speed (a 16Mbps version is in development) is considerably slower than the 10Mbps speed commonly found on PC Card Ethernet adapters, Clarinet's LAN gurus believe that the elimination of all the wires and cables needed with PCMCIA adapters more than compensates for the speed difference. Like EthIR LAN, RF-based LAN systems eliminate wire clutter, but use a shared connection running at only 2Mbps and raise security issues in terms of access to sensitive material being transmitted to and from the LAN.

In addition, since the overwhelming majority of notebooks aimed at the corporate market already have IR ports, no wiring infrastructure changes are required, significantly reducing installation costs. Further, since infrared ports use much less power than any devices that would use a PCMCIA port, battery life is significantly extended compared to notebooks using either PC Card-based Ethernet or RF LAN adapters.