Wireless data card carries connections

Raising the bar on "always connected," the Nokia D211 wireless network card keeps notebook PC users on the air via low-cost 802.11b or pricier wireless carrier data plans, all at the flick of a software switch. Wireless local- and wide-area network coverage comes over three formats-11 Mbits/second by 802.11b, up to 40.2 kbits/s by General Packet Radio Service (GPRS) or up to 43.2 kbits/s by High Speed Switched Circuit Data (HSCSD). The latter two are cellular-based data standards.

The D211's circuitry is supported on a single eight-layer microvia printed-circuit board that incorporates two integral antennas, one for 802.11 and the other for dual-band cellular GPRS/HSCSD. Hardware for the two network interface paths is distributed across both sides of the Type II PC Card format assembly.

Custom components are used for the cellular data protocols-a practice that's common with other Nokia wireless products. Based on internal die markings, Texas Instruments fabricates the baseband processor and STMicroelectronics makes the transceiver and analog interface. A dual-band power amplifier-likely sourced from RF Micro Devices-completes the WWAN function. In most respects, the GPRS/HSCSD components function like a voiceless cell phone, with the emphasis on data rather than talk.

For WLAN connectivity, Nokia selected Globespan Virata's Prism (formerly owned by Intersil) 2.4-GHz WLAN chip set, which consists in this case of the HFA3861B direct-sequence spread-spectrum baseband processor; the HFA3783 I/Q modem and synthesizer; a HFA3845 WLAN media-access controller; and an ISL3685 RF/IF converter and synthesizer. I believe the GPRS/HSCSD data pipes through the HFA3845 to reach the PC Card interface, with this external data port option being the enhancement in the HFA3845 over the catalog HFA3842 802.11 part.

External memory for the D211 comes in the form of 256 kbytes of Samsung SRAM memory, 4 Mbytes of NOR flash from STMicroelectronics and a small Atmel E2PROM.

Based on manufacturing cost estimates, the D211 card cost-of-goods-sold is around $75, a mere 23 percent of the $320 street price for the product. Healthy margins indeed.

A likely evolution for this class of product-and perhaps the most surprising omission of the D211 design-is voice communication. A modest addition to the component set would have short-circuited the question, "Where's the phone?!"

David Carey is president of Portelligent (www.teardown.com). The Austin, Texas, company produces teardown reports and related industry research on wireless, mobile and personal electronics.

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