New Intersil chipset unites 802.11a, b and g standards

Wireless networks are taking the business and consumer worlds by storm, but incompatibilities between emerging standards still cause uneasiness in some users and network administrators looking to make the move to wireless. Network product maker Intersil Corp. is promising to change that with its new PRISM Duette, a chipset that can be used in future generations of wireless devices.

Alphabet soup

The vast majority of wireless LAN devices on the market today operate according to the IEEE 802.11b specification, including Apple Computer Inc.'s AirPort products. This industry standard permits computers to transfer data without using network cables at around 11Mbps, the same speed as a conventional wired Ethernet 10baseT network. 802.11b-compliant devices send and receive data in the same frequency range as many digital cordless phones -- 2.4GHz.

802.11a is a more expensive and less ubiquitous standard, but it's slowly gaining acceptance in environments where considerably higher transfer rates are needed than 802.11b allows, but where the convenience of wireless networking is still sought. 802.11a-compliant devices can operate at up to 54Mbps, almost five times faster than 802.11b devices. Unfortunately, 802.11a -- which operates in the 5GHz range -- is not backward compatible with the 802.11b specification, requiring users and companies who have already made an investment in 802.11b equipment to replace it.

To add further confusion to the mix, 802.11g is another emerging wireless networking standard. 802.11g operates at about the same speed at 802.11a -- 54Mbps -- but works in the same frequency range as 802.11b. 802.11g is backward compatible with the slower 802.11b standard, but not with 802.11a. And because 802.11g operates in the same frequency range as 802.11b devices, the faster standard is subject to the same kinds of limitations and interference problems that sometimes plague 802.11b users. In fact, the wireless LAN industry is awash in fierce contention about the shortcomings and strengths of both faster specifications. 802.11g-compliant devices are promised for later this year and early next year, but the technology isn't already in the marketplace like 802.11a is.

Bridging the gap

As a result of all this, organizations looking to maximize their investment in wired technology are faced with a couple of different quandaries: Adopt 802.11a now and sacrifice backward compatibility with devices that are already wireless. Wait for 802.11g to take hold and migrate then, but limit network usage to what 802.11g offers. Devices that work with all existing wireless LAN standards gain an obvious appeal to some network managers, and Intersil is counting on that as they ready their new PRISM Duette chipset for production, which they're hoping to see in retail products in 2003.

Intersil Wireless Product Group vice president and general manager Larry Ciaccia said that the company's goal has been to ensure that wireless LANs operating at 2.4GHz and 5GHz "are complementary technologies" that offer as much flexibility as possible. "Our unique two-chip solution will enable seamless mobility between 2.4GHz and 5GHz [wireless LANs] and provides a compelling solution for our customers," he said.

The PRISM Duette chipset features an integrated Baseband Processor and Medium Access Controller (BBP/MAC) and direct down conversion (ZIF) architecture. The chipset utilizes a dual-band OFDM-based (Orthogonal Frequncy Division Multiplexing) technology which enables it to operate both with 2.4GHz and 5GHz devices.

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