Data communication method and data communication system, and battery charging apparatus and method

摘要

To execute processing for installing driver software reliably and in comparatively simple fashion, a device including an EEPROM and a device controller are connected using a cable in accordance with IEEE 1394, and driver software of a plurality of types is stored in the EEPROM. Whether driver software suitable for controlling the device has been stored in the device is judged by the device controller. If suitable driver software has been stored, then this driver software is transmitted from the device to the device controller. The driver software proceeds to control the device based upon driver software that has been transmitted. A battery is charged utilizing electric power provided by a power supply line included in a cable that is in accordance with IEEE 1394. A charging apparatus and a personal computer are connected together by the cable. A power source unit in the personal computer converts AC voltage to direct voltage and supplies the DC voltage to the power supply line. The voltage is applied to a charging circuit via the power supply line, thereby charging the battery. A signal line included in the cable is used when the charging apparatus and personal computer send and receive data to and from each other.