Switch 1 turns on and off DMA (Direct Memory Access). See the article "Apple II High-Speed SCSI Card: Setting DMA" for more information on this subject.
The computer's SCSI ID number is determined by the positions of switches 2, 3, and 4 on the SCSI card. Follow these steps to reset the computer's SCSI ID number:
1. Switch the computer off, but leave the power cord plugged in.
2. Choose an appropriate SCSI ID number for the computer. If you are
using a LaserWriter IISC, Personal LaserWriter SC or Apple Scanner, use
the settings for SCSI ID 2.
3. Refer to the information that follows for the correct position of
switches 2, 3, and 4.
Switch indication
-----------------
0 = Open or off x = Closed or on
SCSI SCSI SCSI SCSI SCSI SCSI SCSI SCSI
ID 0 ID 1 ID 2 ID 3 ID 4 ID 5 ID 6 ID 7
OPEN OPEN OPEN OPEN OPEN OPEN OPEN OPEN
1234 1234 1234 1234 1234 1234 1234 1234
---- ---- ---- ---- ---- ---- ---- ----
000 00 0 0 0 00 0 0
x x x x x x xx xx xx x xxx xxxx
4. Be sure to follow the installation instructions in the Apple II High-Speed
SCSI Card Owners Guide to install the SCSI card.
Article Change History:
15 Nov 1996 - Reviewed for technical accuracy, revised formatting.