The PCL-731 is a 48-way digital input/output card that provides 48 parallel digital input/output ports. Simulated programmable parallel I/O interface chip 8255 mode 0, providing higher drive capability of input and output buffers. The 48-bit I/O port of the board is divided into 6 8-bit I/O ports: A0, B0, C0, A1, B1, and C1, each of which can be set to input or output by software. Equipped with two 50-pin interfaces, the pin definition is fully compatible with Opto-22 modules. The 0th bit of PC0 and PC1 ports can generate interrupts IRQ2~7.