ICS Advent DUAL232/AT Series, Product Manual, Page: 14 / 28

Manual Number: 00750-010-3 Page 7
Set jumpers to “S” for shared interrupt mode for all ports sharing an IRQ . Then set one of the ports
sharing an IRQ to “S” & “R”. This provides the pull-down resistor circuit that makes sharing of
IRQ’s possible. “R” and “S” should only be used when sharing an interrupt.
If you are using more than one DUAL232/AT: (3088) or a compatible card in a bus sharing a single
interrupt, you should only have one port set to “R”.
Figure 3-5: Header E3 “Shared Mode” with a compatible card providing the
pull down resistor
Remove all jumpers on E3 to simulate a common serial port with out any interrupt line control.