Epson 1680 Manual page 16

If you add the scanner to a system in which one of your SCSI devices already has a
SCSI ID of 2, change the ID number to an unused number using the rotary switch. See
the table below as a guide.
ID Availability
0 Not available for Macintosh
Not recommended for PCs
1 Not recommended
2 Available
3 Available
4 Available
5 Available
6 Available
7 Not available for Macintosh
May not be available for PCs.
Not available
c
*Scanner will not work if selected.
Caution:
Do not set the SCSI ID to an ID number that is already assigned to another
device. Otherwise the computer, scanner, and other devices will not operate
properly.
16
Description
Used for hard disks
Usually used for hard disks
Usually used for hard disks
Factory setting of the scanner
Not available if your Macin-
tosh has a built-in
CD-ROM
Always used for the Macin-
tosh itself
Usually used for the PC's SCSI
board
For transportation purposes.*
See "Transporting the Scan-
ner and the Transparency
Unit" in the Maintenance and
Troubleshooting section of
the online Reference Guide.