Set of electronic apparatuses having first and second electronic devices, and computer program product

A portable audio player ( 100 ) includes a decoder ( 14 ) and other devices for reproducing audio data, a microcomputer ( 16 ) for controlling starting and stopping the reproduction, and a radio communication device ( 24 ). An on-vehicle audio player ( 200 ) includes a radio communication device ( 64 ) for a bidirectional radio communication with the radio communication device in the portable audio player, a decoder ( 54 ) and other devices for reproducing audio data, and a microcomputer ( 56 ) for controlling starting and stopping the reproduction. In case that the portable audio player stops reproducing the audio data, the on-vehicle audio player starts reproducing the audio data.