| 摘要 |
PURPOSE:To surely send a reproduction data from other disk reproducing device by sending a digital data supplied externally via an optical cable to an optical cable automatically when a main power supply is interrupted. CONSTITUTION:When a main power supply circuit 37 is interrupted, since the output of a NAND circuit 29a is fixed to an H level regardless of a selection control signal SDIR in a selection circuit 30, a data SEXAUDA supplied externally via an optical cable 25 is switched forcedly so as to be led to an optical data transmission circuit 35. When the external data SEXAUDA is received through the optical cable 25, a voltage V+ at a noninverting input terminal + of a comparator 45 is a half of a backup voltage VBAK and higher than a reference voltage VR, then the output of the comparator 45 goes to an H level and a transistor(TR) Q1 is turned on. Thus, a driving current is supplied from the backup voltage VBAK to a light emitting diode 34 and the received data SEXAUDA is sent to an optical cable 36. |
