Patent ID: 7574318

Claim:
An I/O port tester configured for testing input/output (I/ 0 ) ports of an electrical device, the I/O port tester comprising: a first relay having a switch connected to a first resistor in series, and an inductance coil; a second relay having a switch connected to a second resistor in series, and an inductance coil; a plurality of serial plugs configured for respectively inserting into serial ports of the electrical device, wherein the plurality of serial plugs is configured for receiving a test signal from the electrical device via one half of the plurality of serial plugs and returning the test signal to the electrical device via the other half of the plurality of serial plugs, to detect the serial ports of the electrical device; a water sensor plug corresponding to a water sensor port of the electrical device; a direct current (DC) voltage plug connected to the water sensor plug via the switch of the first relay and the first resistor, and connected to the water sensor plug via the switch of the second relay and the second resistor, the first and second resistors respectively configured for simulating a water-sensor wire in a dry condition and a water-sensor wire in a wet condition; and two data plugs respectively connected to the inductance coils of the first and second relays, wherein the two data plugs are configured for receiving control signals from the electrical device to control the switch of the first relay and the switch of the second relay; the switch of the first relay is configured for testing electrical device working in a dry condition, and the switch of the second relay is configured for testing the electrical device working in a wet condition.