6
FOUR PORT RS-232 SERIAL INTERFACE
NOTE
Be sure to set the address selections and jumper options before
installation.
The board contains several jumper straps for each port which must be set for
proper operation.
4.1 Port Enable/Disable
Each port on the Four Port RS-232 can be enabled or disabled with switch
position 8 on the DIP switch. The port is enabled with the switch ON (or
closed) and disabled when OFF (or open). If any port is disabled, be sure to
also disable the interrupt request for that port by removing the IRQ jumper.
Headers E1–E4 select the IRQ for each serial port. If COM1: is selected, this
jumper must be on the IRQ4 setting. If COM2: is selected, this jumper must
be on IRQ3.
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 best setting. Check your software configuration
instructions to determine the most appropriate IRQ setting.
4. Option Selection
