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 le | 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 primary port.
If you install a video card with a parallel port (such as an IBM monochrome 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:.