The Foster City, California-based RDC Networks Inc subsidiary of Jerusalem, Israel-based RDC Communications Ltd claims to have a wireless local area network system that has a range 2.5 times greater than its nearest competitor. The PortLAN system is said to operate over a 2,700 foot radius in a free space environment, representing an area of 22.9m square feet. PortLAN is based on Spread Spectrum Frequency Hopping in the unlicensed 2.4GHz frequency band. The system consists of an Access Point (which controls the wireless cell and acts as a bridge to the Ethernet backbone) and the User Unit, an AT or PC Card adaptor that incorporates a small radio unit. It supports most popular network operating systems, said RDC, including NetWare, LAN Manager and TCP/IP-based networks. PortLAN is claimed to achieve greater distances than other systems using Spread Spectrum Frequency Hopping – for example Proxim Inc’s RangeLAN – through two key features: firstly, the company claims to have developed a highly efficient Media Access Control layer networking protocol, enabling it to cope with a higher level of noise and interference. This, said the company, enables the system to deal with a Bit Error Rate of 10-3, where other systems lose communication at 10-5 or 10-4 Bit Error Rate. Secondly, RDC claims to have implemented a unique Antenna Diversity feature, which comprises two antennae at the access point for superior signal propagation quality. In terms of security, PortLAN is said to include scrambling, as well as authorisation of the User Unit by the Access Point based on its physical address. There is an optional Simple Network Management Protocol agent, and the Israeli company has also launched a graphical management application, which runs under HP OpenView for Windows. Po rtLAN is shipping now, and it is priced at $700 for the User Unit, and $2,200 for the Access Point.
