| 摘要 |
PURPOSE:To prevent the malfunction of an apparatus due to the erroneous insertion of a plug by setting the impedance RO of a commander for remote control to a value which a device, which can be inserted to the same jack, cannot have normally and detecting this value. CONSTITUTION:The value RO of the impedance 23 in the side of the commander 2 is the impedance of a device whose jack can be inserted with a plug erroneously, and the value RO is set to satisfy RL<RO<RH where a maximum value lower than the value RO and a minimum value higher than the value RO are denoted as RL and RH respectively. A system controller 10 in the side of the electronic apparatus is provided with a detecting circuit 12 which detects the impedance of a connected device. When the plug is inserted, an impedance RZ of the device is connected between a connection point P and the earth, and a voltage V1 at the connection point P is changed by the impedence RZ as down by a solid line 30 in Fig. If a switch 22 is turned off when a plug 21 of the commander 2 is inserted to a jack 11, VI>VH is true, and a transistor TR 15 is turned off, and a control signal CL is in the high level still, and a camera and a VTR are stopped together. When an earphone or the like is inserted erroneously, malfunction is not generated because of RZ<RL. |
