Input and output switching value test system

The utility model relates to the train maintenance technology field, and especially relates to an input and output switching value test system. The input and output switching value test system comprises a plurality of output test plates, a plurality of input test plates and an upper computer. The output test plates are in cascade connection, and are communicated with the upper computer through an RS485 bus. The input test plates are in cascade connection, and are communicated with the upper computer through an RS485 bus. The test system employs the RS485 buses to communicate with the upper computer, can be in cascade connection with a plurality of board cards, and can meet requirements of any I/O port. Only backboard connection plug and distribution wires are replaced aimed to different switching value approaches and plates to be tested of different board card interfaces, change of the whole system is not needed, versatility of the input and output switching value test system can be achieved, the hardware development cost can be lowered and the development cycle is shortened.