| 摘要 |
PURPOSE: To prevent the transmission part of a radio equipment from abnormally oscillating or breaking by inhibiting the transmission part from operating even when a press-to-talk switch is pressed by mistake unless a load such as an antenna is connected to the transmission part and to inform the operator by generating an alarm sound. CONSTITUTION: A push-button switch 4 is provided by an antenna plug 2 to detect whether or not the external antenna is connected and the detection result is ANDed 5 with the state of the press-to-talk switch 3 to judge whether or not transmission is ready and perform control 9. Further, the state of the push- button switch and the state of the press-to-talk switch are ORed to generate the alarm sound if the press-to-talk switch is pressed when the external antenna is not connected. |
