The Symbol Spectrum24t chipset is specific for Symbol-based cards including Nortel Emobility 4121, 3Com AirConnect, Intel PRO/Wireless, and Symbol Wireless Networker Cards. Ericsson WLAN cards are also Symbol-based, but have a separate Linux driver (eriwlan). Symbol cards are Prism II cards with their own MAC layer controller. Surprisingly, under Linux they are supported by the orinoco driver (read the orinoco.c source) and are similar to Hermes chipset cards in terms of configuration and usefulness in the penetration testing of WLANs. Symbol CF cards have an orinoco and spectrum24t-based driver that is different, as these cards don't have built-in firmware. At http://www.red-bean.com/~proski/symbol/readme, you can find more information about "no-firmware" Symbol cards and download a Spectrum24 Linux driver. However, for Layer 2 traffic analysis in the monitor mode, the morinoco patch (http://www.cs.umd.edu/~moustafa/morinoco/morinoco.html) has to be applied. Jesus Molina provides a package of the Spectrum24 CF driver already patched with the morinoco patch with some additional old kernel versions for backward compatibility. A good example of a common Symbol chipset card is a low-power Socket CF card from Socketcom. Although this card does save your PDA battery power, it has a lower transmitting and receiving range compared to more power-hungry cards, but always remember that everything comes with a price. The precompiled packages of Spectrum24 Linux driver (kernel 2.4.18) for this card, patched for monitor mode frame capture and supplemented by useful comments on configuring the card, are available at http://www.handhelds.org/~nils/socket-cf-wlan.html.