DIP switch set 2 (parallel and serial port operations)
The parallel and serial port functions controlled by DIP switch set 2 are
listed in Table 1-3 and described below.
Table 1-3. DIP switch set 2
1
2
3
4
Parallel
Primary
OFF
ON
Secondary
OFF OFF
D i s a b l e
ON
ON
Serial
Primary
OFF
OFF
Secondary
ON OFF
Disable
—
ON
Switches 1, 2, 3, and 4 tell the computer how to access the built-in parallel
and serial ports. You do not need to change the factory settings unless you
install an option card with an additional parallel or serial port. If you do
install such an option card, read the following information carefully.
Switches
1 and 2
(parallel
port)-tell the computer how to access the built-in
parallel port.
The built-in parallel port functions as either the primary or secondary
parallel port. However, if you install any option card with its own parallel
port, you must set these two DIP switches so there is no conflict between the
built-in parallel port and the added card. Table 1-3 shows you how to set the
DIP switches.
If you install an option card that has only a parallel port, you must
designate this as the secondary port and leave the built-in port as the pri-
mary port.
If you install a video card with a parallel port (such as an IBM mono-
chrome display and printer adapter) you must designate it as the primary
parallel port and the built-in port becomes the secondary parallel port.
If you install two option cards with parallel ports, one is designated as
the primary port and the other as the secondary port. In this case, you need
to set switches 1 and 2 on in order to disable the built-in port.
If MS-DOS searches the system for a parallel port and finds only one, it
names it LPTl:. If there are two parallel ports, it names the primary port
LPTl: and the secondary LPT2:.
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