Black Box IC171C manual Option Selection

CHAPTER 4: Option Selection

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Figure 4-2. Header E1 Optional Windows 3.1 Configuration. IRQ 10

selected. (Refer to Chapter 6 for more information.)

NOTE

IRQ 2 on AT class machines is not available. IRQ 9 is substituted in place of IRQ 2. To select IRQ 9, place the jumper on the IRQ 2 position.

E2: “N” indicates the (N)ormal, single-interrupt-per-port mode. The “S” indicates the (S)hared interrupt mode, which allows more than one port to access a single IRQ. This is the preferred Windows and OS/2 setting.

N S M

Figure 4-3. Header E2 in Normal Mode.

Set jumpers to “N” for single interrupt mode. This setting is the normal setting for most applications.

Set jumpers to “S” for shared interrupt mode for all ports sharing an IRQ except for one. Set one of the ports sharing an IRQ to “M.” This provides the pull-down resistor circuit that makes sharing of IRQs possible.

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