| abstract |
[PROBLEMS] To freely use both of the two downstream sound signal lines (71, 72) for purposes other than power transmission while receiving power necessary for operation from a main device represented by a smartphone, Realize more advanced peripheral functions by making it possible to use one upstream sound signal line (8). Operation is performed using a bias voltage supplied from the main device side via a third plug electrode (P3) and a fourth plug electrode (P4) of a four-pole phone plug (P), and Sound signal input line (71, 72) leading to the plug electrode (P1) and / or the second plug electrode (P2), and / or sound signal output line leading to the third plug electrode (P3) ( 8) and a peripheral function realization unit (34) for realizing a predetermined function as a peripheral device. [Selection] Figure 6 |