Canon DR-3080C - Manual (Page 22)

18 Installing the Scanner
Terminator Setting
The terminator should be set to "ON" only in the SCSI device that is at the
end of the SCSI daisy chain.
If the scanner is the only SCSI device that is being connected to the PC, or if
the scanner is being connected at the end of a daisy chain of SCSI devices, set
bit 1 of the scanner's DIP switch (terminator) to ON, and disable terminator
for all other SCSI devices.
Terminator OFF Terminator ON
If another SCSI device is located at the end of the daisy chain, turn the
scanner's terminator "OFF," and turn the terminator in the last SCSI device
"ON."
Terminator ON
(or attached) Terminator OFF
CAUTION
When the scanner is the last device on the SCSI bus, enable
termination either by DIP switch or by attaching a terminator plug.
Note that incorrect operation may result if a terminator plug is
attached while termination is enabled by DIP swtich.