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W&T
W W W . W u T . D E
Base addresses
The I/O base addresses of the two ports can be set independently by DIP switches to 03F8H, 02F8H, 03E8H or
02E8H. Serial ports at these base addresses are recognized by almost all modern BIOS versions upon startup of
the PC, and are written to the BIOS RAM of the computer. Some older BIOS versions recognize only two serial ports
at the base addresses for COM1 and COM2. In these rare cases, a separate program is needed to search the
computer for installed serial ports and write the COM3 and COM4 ports to BIOS RAM. The necessary software can
be obtained from W&T on request. Setting both ports to the same base address should be strictly avoided.
Please
see the following tables for an explanation of the address DIP switch settings:
Since the address is decoded by means of GALs, customizing of the I/O address is no problem. This option makes
it possible to employ more than 4 serial ports on a computer, if the software permits the use of additional I/O
addresses.
Interrupt settings
The W&T serial PC Cards permit use of the standard interrupts IRQ3 and IRQ4 for the serial ports COM1 and
COM2, and interrupts IRQ5 and IRQ7 for the parallel ports LPT1 and LPT2 if the system has no parallel ports or if
the built-in parallel ports do not operate in interrupt mode. Since it is a long card, the PC Card 16201 also supports
interrupts IRQ9..IRQ12 of the second interrupt controller. Please see the following tables for an explanation of the
IRQ DIP switch setting:
Interrupt setting port 1
Interrupt setting port 2
Port 1
SW 1.9
SW 1.10
SW 1.11
Disabled
X
X
OFF
COM1
03F8H
OFF
OFF
ON
COM2
02F8H
ON
OFF
ON
COM3
03E8H
OFF
ON
ON
COM4
02E8H
ON
ON
ON
Port 2
SW 2.9
SW 2.10
SW 2.11
Disabled
X
X
OFF
COM1
03F8H
OFF
OFF
ON
COM2
02F8H
ON
OFF
ON
COM3
03E8H
OFF
ON
ON
COM4
02E8H
ON
ON
ON
IRQ
SW 1.1
SW 1.2
SW 1.3
SW 1.4
SW 1.5
SW 1.6
SW 1.7
SW 1.8
-
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
3
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
4
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
5
OFF
OFF
OFF
OFF
OFF
ON
OFF
OFF
7
OFF
OFF
OFF
OFF
OFF
OFF
ON
OFF
9
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
10
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
11
OFF
ON
OFF
OFF
OFF
OFF
OFF
OFF
12
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
IRQ
SW 2.1
SW 2.2
SW 2.3
SW 2.4
SW 2.5
SW 2.6
SW 2.7
SW 2.8
-
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
3
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
4
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
5
OFF
OFF
OFF
OFF
OFF
ON
OFF
OFF
7
OFF
OFF
OFF
OFF
OFF
OFF
ON
OFF
9
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
10
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
11
OFF
ON
OFF
OFF
OFF
OFF
OFF
OFF
12
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
SW 2.12 has
no function
SW 1.12 has
no function
PC card 2 x 20mA
#13401
