The AD1 1-Bay Communications Dock is an accessory for the CK30 and CK31 Handheld Computers. You can use the AD1 to power the CK30 or CK31, to charge the battery while it is in a CK30 or CK31, to transfer data and applications using RS-232 serial communications, to transfer data and applications through a 10BaseT/100BaseTx Ethernet connection, and to transfer data and applications through a USB (universal serial bus) Type B connection.