| 摘要 |
<p>PURPOSE:To realize a desired combination of transmission and reception without replacing plugs, etc., by constituting a predetermined combination of transmission and reception circuits according to the operation of a flip-flop which is set with the 1st PTT button and reset with the 2nd PTT button, and performing transmission and reception by the touch operation of the 2nd PTT button. CONSTITUTION:When the 2nd PTT button PT2 is touched, a one-shot pulse generating circuit 16 operates a T flip-flop(TFF) 17, whose Q terminal is held at the H level, thereby setting a flip-flop(FF) 18. When the button PT2 is touched again, the TFF 17 falls to the L level and a main body 1 gets ready for reception by its transmission/reception switch 8. A timer circuit 20 counts a time set with a volume 21 and resets itself to an initial count value when the Q terminal of the TFF rises from the L level to the H level. When a specific value is counted, the circuit 16 is driven and the counter is not reset until the Q terminal of the TFF 17 goes up to the H level. When the button PT2 is touched for the 2nd time in the middle of the counting operation of the circuit 20, the TFF 17 is reset and the circuit 20 is initialized, thereby entering reception. When the 1st PTT button PT4 of a microphone unit 4 is operated, the FF 18 is reset unconditionally and the TFF 17 is reset.</p> |
