Found a better way:
ZThinCableTM also provides the gender your looking for when you want to attach peripherals to your Zaurus. ZThinCable provides DB-9 male and DB-9 female connector options allowing you to plug directly into your modem, GPS, sensor, or other RS-232 serial device. This eliminates the need for null modem cables, gender changers and other \'plumbing\' that is required for using the Sharp CE-170TS with devices such as modems, GPS receivers, and Cisco equipment.
Altough you need to keep the keyboard closed on the 6000 series. You can open it on all the other models.