Impulse 3440 - Manual (Page 7)

Card Setup
Sealevel Systems ULTRA COMM+422 Page 4
Jumper Selections
For ease of configuration, the headers are grouped by port. Port one headers
have a ‘J1’ prefix; Port two headers have the ‘J2’ prefix, etc. For example, the
header that controls the Port one IRQ selection is J1B; the header that controls
the Port 2 IRQ selection is J2B. The silk-screen also provides information for
configuring the adapter without the use of the manual. This is particularly useful
in field re-configuration.
IRQ Selection
Headers J1B through J4B select the interrupt request for each serial port. If
COM1: is selected, the corresponding jumper must be on the IRQ4 setting. If
COM2: is selected, the corresponding jumper must be on IRQ3.
3 4 5 6 7 10 11 12 15 9
Figure 4 – Headers J1B – J4B, IRQ Selection
Note: Most communications software applications default COM3: to IRQ4 and
COM4: to IRQ3. This requires the sharing of interrupts between COM1:
and COM3:, and between COM2: and COM4:. While this is the default, it
is not always the preferred setting. Check your software configuration
instructions to determine the most appropriate IRQ selection.
Any two or more ports can share a common IRQ by placing the jumpers on the
same IRQ setting and setting the appropriate selections at J1A through J4A.
Consult your particular software for IRQ selection. If no interrupt is desired,
remove the jumper.