5.1 Functions of the CU-300The optical communication unit CU-300 series is available in three models: CU-301, CU-321 andCU-311. The CU-300 series has the following functions:(1) Data exchange functionThe CU-300 exchanges data and programs between the BHT and the host PC.It interfaces with the BHT via the IrDA interface and with the host PC via the RS-232C interface(CU-301), USB interface (CU-321) or Ethernet 10Base-T interface (CU-311).(2) Battery cartridge charging functionThe CU-300 charges the lithium-ion battery cartridge loaded in the BHT.NOTE: Before using the CU-321, you need to install the dedicated USB device driver stored in theCD-ROM that comes with the CU-321. For the installation/uninstallation procedure, refer to theguidebook that comes with the CU-321.140
