A power supply system capable of providing electric power to an electronic device having a first battery includes a battery pack (100) and an attachment apparatus (300). The battery pack includes a body (110) having at least a first recess (221), a second ...

A holder, electrical supply, and optional RF transmitter unit to hold, supply power to, and receive a data signal from an operating electronic device when the device (e.g., MP3 player) is held in the unit is disclosed. Electrical power enters the unit's po...