| 摘要 |
The system includes a relay (1) which may be mechanical or an electronic equivalent. The relay is powered from the remote control circuit (6) or from an external circuit. The relay may be set off directly from the computer port (5) or a diode (7) may be required to set the trigger potential. An alternative might involve an electronic circuit connected to the port represented by a simple common emitter transistor circuit whose base resistor is connected to the port. In the case of ports at negative potential such as RS232, the relay responds to those potentials. The relay may also replace the manual switch entirely. |
