Model 104-II32-4RO is a 36-channel PC/104 utility board featuring 32 fully optically isolated digital inputs and four handy relay outputs. The inputs may be driven by either DC sources of 3-31V (or higher by special order) or AC sources at frequencies of 40Hz to 10KHz. Optically isolating the digital inputs from each other, and from the computer, assures smooth, error-free data transmission in noisy, real-world environments. All I/O connections are made via one 34-pin and one 50-pin right angle header (vertical headers available upon request). Each input circuit includes a jumper selectable slow/fast filter to accommodate AC inputs and is also useful for slow DC inputs in noisy environments. The filter may be manually disabled to increase the boards typical response time to 10 usec when used with faster DC inputs. The input impedance is 1.8K Ohms to accommodate a wide input range. To prevent erroneous input state change detections and interrupts, Schmitt triggers are used which provides a solid logic signal to the computer interface. The electromechanical relays are more flexible than FET and solid state outputs in regards to the kind of signals that can be switched. Another cool feature of the board is a fused +5V at the connector which can be used with a wrap plug for an easy test setup to quickly verify proper operation of the boards 32 inputs, change of state detection IRQ’s and 4 relays without any additional test equipment! System interrupts are software controlled, enabling the board to generate an interrupt whenever one or more of the isolated digital inputs changes state. When an interrupt is received a provided ISR (Interrupt Service Routine) handles the request, polls the card once to read the state change then clears the interrupt, enabling the board to detect the next change without processor intervention. IRQ Sharing with other ISA system devices is enabled for ease of system development and installation.