== Clamshell models The 750,760,860,1000,3x00 have a dual-purpose headphone/microphone socket. When the audio driver is used for audio-in one channel is switched to a microphone input.
It is thus possible to use a universal headset (usually designed for home cordless telephones) with a 2.5mm jack plug with three connection rings, with a 2.5 to 3.5 adaptor, and plug it into the Z to VOIP calls.
The 6000 has a built-in microphone and speaker, so can be used directly, quality suffers due to echo, so a headset is ideal; in this case the 6000 has a 2.5mm jack. I think that the same universal headset should work.
== Other headsets
Note that some headsets with 2.5mm jack plugs have four connector rings on the tube, these are designed for mobile phones, with the extra connector being for a push button to answer or dial. These might not be suitable for the Zaurus, but they are useful if you have an Audiovox RTM8000 gsm/grps compact flash modem card (it might also work with an Enfora, but I am not sure)