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Wireless Hacks by Rob Flickenger

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Client Capability Reference Chart

A quick guide to what’s what in the world of consumer wireless gear.

Wi-Fi has decidedly shifted from a niche market to a mass market in just a little over a year. As a result, there is a bewildering assortment of wireless equipment available on the market. While the various descriptions will dazzle you with the latest bells, whistles, and didgeridoos, most wireless hackery requires only the answer to a few key questions: How much does it cost? How much power does it put out? How sensitive is the radio? What other equipment will it communicate with?

Unfortunately, the answer to the first question (“How much does it cost?”) is changing so rapidly that by the time this book makes it to press, anything I included here would be irrelevant. While new hardware is being introduced all the time, the specifications of existing hardware remain relatively unchanged. Table 4-2 shows the vital statistics of many popular radio cards.

For brevity, the table’s Receive Sensitivity column uses the following convention: the numbers are the power levels required (in dBm) to receive data at 11 Mbps, 5.5 Mbps, 2 Mbps, and 1 Mbps respectively. Remember that these are negative numbers, so, for example, a rating of -94 is much more sensitive than a rating of -87 (by a whopping 7 dB!) A “*” means that the rating for that speed is unavailable.

Table 4-2. Common wireless client capabilities matrix

Name

Interface

Tx power

Rx sensitivity

Antenna connector

Chipset

3Com AirConnect

PCMCIA

30mW

-81 / -84 / -85 / -87

Dual MMCX

Prism 2.5

Addtron AWP-100

PCMCIA

20mW

-76 / * / * / -80

None

Prism

Cisco 340(AIR-LMC340)

PCMCIA

30mW

-83/-87/-88/-90

Dual MMCX

Aironet

Cisco 350 (AIR-LMC350)

PCMCIA

100mW

-85/-89/-91/-94

Dual MMCX

Aironet

D-Link DWL-520

PCI

30mW

-80/-83/-86/-89

Reverse SMA

Prism

D-Link DWL-650

PCMCIA

30mW

-84/-87/*/-90

None

Prism 2

D-Link DWL-650+(proprietary 22Mb)

CardBus

30mW

unpublished?

None

TI

EnGenius/Senao/NetGate(2511 Plus EXT2)

PCMCIA

200mW

-89/-91/-93/-95

Dual MMCX

Prism 2.5

EnGenius/Senao/NetGate(2011CD)

PCMCIA

100mW

-87/-89/-91/-93

Dual MMCX

Prism 2.5

Linksys WPC11

PCMCIA

25mW

-76/*/*/-80

None

Prism 2

Linksys WMP11

PCI

30mW

-82/*/*/*

Reverse SMA

Prism 2

NetGear MA101

USB

20mW

-84/-87/-89/-91

None

n/a

NetGear MA401

PCMCIA

30mW

*/*/*/*

None

Prism 2

Orinoco(Silver or Gold)

PCMCIA

30mW

-82/-87/-91/-94

Lucent

Hermes

ZcomMax(XI-325H)

PCMCIA

100mW

-92/*/*/-85

MMCX

Prism 2.5

Note that some client cards use minor variations under the same trade name. For example, the Cisco Aironet series can come with or without external antenna connectors. Units with AIR-PCM model numbers have permanent molded antenna connectors, while AIR-LMC models have external connectors with no internal antenna. Likewise, some manufacturers offer cards with different transmit power under similar names, but that have different model numbers. Be sure to check your model numbers before purchasing!

There is an interactive hardware capability chart available from Seattle-Wireless (http://seattlewireless.net/index.cgi/HardwareComparison). This chart is generally kept up to date as new equipment appears on the market, and can be particularly handy, since some manufacturers bury the technical details of their products in the back of the manual (if they publish them at all). If you have a piece of hardware that isn’t listed, you can add it to the list yourself, and save other people the effort of digging around for the real specs.

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