| 摘要 |
PROBLEM TO BE SOLVED: To provide a communications device capable of enabling both protection of a communication part and stability in transmission state.SOLUTION: In a communications device, a switch part 3 is provided on a line that connects a communication antenna part 1 and a communication part 2. In a case where there is no connection instruction signal from a switch control part 4 to a switch part 3 through a step-up circuit part 41, the switch part 3 cuts off the line. In a case where there is a connection instruction signal from the switch control part to the switch part through the step-up circuit part, the switch part 3 electrifies the line. The switch control part 4 detects a voltage of a reception signal at the communication antenna part 1. In a case where the voltage of the detected reception signal exceeds a predetermined value, the switch part 3 cuts off the line. In a case of predetermined value, setting is made near an upper limit voltage which applies an overvoltage to the communication part 2. A voltage that has been stepped up by the step-up circuit part 41 is a voltage with which conduction of the line is assured by the switch part 3 in a case where there is signal transmission from the communication part 2. |
