The XScale is an ARM processor.
The 5500s etc. have a SA1110 processor, your 5600 and the CXXX machines have XScale PXA2x0 processors which are also ARM processors.
In fact your PXA chip is able to use the ARM5 instruction set whereas my 5500 can only use the ARM4 set.
Everything is currently written to use the ARM4 instruction set and the PXA is backwards compatible so you\'re fine (in terms of processor type at least) with anythiing you can find written for any Zaurus (and any Linux iPAQ too FYI).
Now that that little matter is cleared up ;-), I\'ve only every used Wellenreiter and kismet to look for networks, not to work out how strong their signals are. This function must have to be, I presume, supported by the drivers. I don\'t know whether it\'s possible but I\'m sure someone like Mickeyl (who was involved in the development of Wellenreiter) could tell you.
Si