Shared interface device

摘要

A shared interface device provides connection between a portable electronic device and a peripheral unit. The shared interface device comprises a switch and an energy-storing element. The switch has a terminal connected to a TxD/POWER pin of the portable electronic device and an RxD pin of the peripheral unit, and another terminal connected to a VCC pin of the peripheral unit. The switch is ON/OFF when the TxD/POWER pin of the portable electronic device is HI/LO. The energy-storing element has one end connected to another end of the switch to supply electrical power to the peripheral unit and another end connected to ground. The energy-storing element is charged when the switch is ON and used as a backup power supply when the switch is OFF.