9
Interrupt request
The interrupt request line used by the modem is configured at the
factory for IRQ3. You may change this setting by reconfiguring
jumper block W1:
Table 1 Interrupt request lines: W1
Pins Jumpered
IRQ
[1-2]
[3-4]*
[5-6]
[7-8]
[9-10]
[11-12]
IRQ2
IRQ3
IRQ4
IRQ5
IRQ6
IRQ7
* = default
Base port address
The 5556 can be configured as COM1, COM2, COM3 or COM4. It is
configured at the factory to operate using COM3. To change the base
port address, you must reconfigure jumper block W1.
Table 2 Base port address: W1
Pins Jumpered
COM port
Address
[13-14]
[15-16]*
[17-18]
[19-20]
COM4
COM3
COM2
COM1
2E8-2Efh
3E8-3Efh
2F8-2FFh
3F8-3FFh
* = default
Note
When using Micro PC Control Cards, be sure not to jumper the 5556
to a COM port that is used on another card. Doing so will cause
erratic and unpredictable results.
