Black Box Computer Hardware IC181C 用户手册

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页码 17
5
CHAPTER 3: Address Selection
NOTE
Be sure to set the address selections and jumper options before
installation.
Each serial port on the Four Port RS-232 Serial Interface occupies 8 con-
secutive I/O locations. DIP switch SW4 sets the base address for Port 1, SW3
for Port 2, SW2 for Port 3, and SW1 for Port 4. Be careful when selecting the
base address as some selections conflict with existing PC ports. The following
table shows several examples that usually do not cause a conflict.
Address
Binary
Switch Position Setting
Hex
A9
A0
1
2
3
4
5
6
7
280-287
1010000XXX
OFF
ON
OFF
ON
ON
ON
ON
2A0-2A7
1010100XXX
OFF
ON
OFF
ON
OFF
ON
ON
2E8-2EF 1011101XXX
OFF
ON
OFF
OFF
OFF
ON
OFF
2F8-2FF
1011111XXX
OFF
ON
OFF
OFF
OFF
OFF
OFF
3E8-3EF 1111101XXX
OFF
OFF
OFF
OFF
OFF
ON
OFF
300-307
1100000XXX
OFF
OFF
ON
ON
ON
ON
ON
328-32F
1100101XXX
OFF
OFF
ON
ON
OFF
ON
OFF
3F8-3FF
1111111XXX
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Typically COM1:=3F8h; COM2:=2F8h; COM3:=3E8h; COM4:=2E8h
The following illustration shows the correlation between the DIP-switch
setting and the address bits used to determine the base address. In the figure
below, the address 300 hex through 307 hex is selected (300 hex =11 0000
0XXX in binary representation, where X is a non-selectable address bit). Note
that setting the switch ON (or closed) corresponds to a “0” in the address,
while leaving it OFF (or open) corresponds to a “1.”
A9
A3
ON
OFF
EN
0
1
1 2 3 4 5 6 7 8
3.  Address Selection