User manual

TREK-775/TREK-776 User Manual 36
4.4 COM-port Interface
The computer provides four serial ports: COM1, COM 2: RS-232/422/
485 (selectable via BIOS setting) and COM3, COM 4: RS-232.
The IRQ and the address ranges for COM1, COM2, COM3 and COM4
are fixed.
However, if it becomes necessary to disable the port or change these
parameters later, it is possible to do so through the system BIOS setup.
The table overleaf shows the default settings for the computer's serial
ports.
COM1 and COM2 are linked as one set. It is possible to exchange the
address range and interrupt IRQ of COM1 for the address range and inter-
rupt IRQ of COM2. After exchanging:
COM1's address range is 2F8 ~ 2FF and its IRQ is IRQ3.
COM2's address range is 3F8 ~ 3FF and its IRQ is IRQ4.
COM3 and COM4 are linked as another set. It is possible to exchange the
address range and interrupt IRQ of COM3 for the address range and inter-
rupt IRQ of COM4. After exchanging:
COM3's address range is 3E8 ~ 3EF and its IRQ is IRQ10.
COM4's address range is 2E8 ~ 2EF and its IRQ is IRQ5.
Table 4.7: Serial port default settings
Port Address Range Interrupt
COM1 3F8 ~ 3FF IRQ4
COM2 2F8 ~ 2FF IRQ3
COM3 3E8 ~ 3EF IRQ10
COM4 2E8 ~ 2EF IRQ 5