| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an input and output circuit of an electronic musical instrument such that a set of terminals are usable as both input terminals and output terminals. <P>SOLUTION: An input circuit 5 comprises a photocoupler 1, resistors 2 and 3, and a diode 4. Further, an output circuit 9 comprises resistors 6 and 7 and an inverter 8. A changeover switch 11 comprises switches 11a, 11b, and 11c. Terminals 12 to 14 are used as input/output terminals. When the changeover switch 11 is switched to its output side, the terminals 12 to 14 are connected to the output circuit 9 as shown in Fig. and those terminals 12 to 14 can be used as the output terminals. When the changeover switch 11 is switched to its input side on the other hand, the terminals 12 to 14 are connected to the input circuit 5 and usable as the input terminals. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
