These cards are 24-bit parallel, digital input/output cards designed for use in PCI-Bus computers. The difference between the models is that I/O connections to PCI-DIO24D are via a standard 37-pin D-sub connector while I/O connections to PCI-DIO24H are via a 50-pin connector. The cards may be installed in any 5V PCI-bus slot in IBM and compatible personal computers. These cards contain a type 8255-5 Programmable Peripheral Interface (PPI) chip. They can be programmed to accept inputs or to provide outputs on three 8-bit ports: designated Ports A, B, and C. Port C can be further divided into two 4-bit nibbles. Each I/O line is buffered by a type 74ABT245B tristate buffer transceiver capable of sourcing 32 mA or sinking 64mA. The buffers are configured under program control for input or output use according to direction control signals from the control register inside the PPI. Pull-ups (to +5 VDC) on the card assure that there are no erroneous outputs at power-up until the card is initialised by system software. Further, jumpers on the card provide a choice to either permanently enable the buffers or to tri-state them under program control. Input/Output wiring connections for the PCI-DIO24D are via a 37-pin D-sub connector on the card mounting bracket. Either a 37-pin D-sub solder cup mating connector or an insulation-displacement ribbon cable can be used for I/O connections. Fused +5 VDC power is available at the I/O connector. A re-settable on-board fuse is rated at 0.5A and can be reset by cycling computer power. Input/Output wiring connections for PCI-DIO24H are via a 50-pin connector on the card mounting bracket. Insulation displacement ribbon cables can be used for I/O connections to termination panels such as ACCES' model STA-50 Screw Terminal card. The pin connections are also compatible with ACCES A24A , Grayhill, OPTO22, Western Reserve Controls, Potter& Brumfield, etc opto-isolated module mounting racks. If needed for external circuits, fused +5VDC power is available at the I/O connector. The resettable 0.5A fuse can be reset by cycling computer power.