The PC-63C Reed Relay Board gives your PC the capability to control up to 16 external devices without requiring any external terminal panels or opto modules. The PC-63C is designed for switching low to medium power levels at high switching speeds. Wait-state generation has been incorporated to allow operation in very fast computers with fast Bus Clock speeds. LEDs on-board tracks status of the Relays. A signal-conditioned external interrupt line allows pulses of up to 24V to be used. It can operate as an external trigger or an automatic startup / shutdown signal. A jumper enables the external interrupt line to be commoned to digital ground or be completely isolated. For a logical Low, you require a voltage of 0 to 2.5V on the external trigger line. For a logical High, you require a voltage from 3V to 24V.