HP 2240 Owner's Manual page 186

SCSI Bus
Differences
A Small Computer Systems Interface (SCSI) bus is an IEEE standard
bus for connecting your workstation to internal and external devices
(SCSI devices) running at different speeds, singly or in combination.
Examples of these SCSI devices are floppy disk drives, 4-mm DDS-
format tape drives, CD-ROM drives, and Winchester hard disk drives.
There are three types of SCSI buses available with this workstation –
a narrow, single-ended (NSE) SCSI bus, a fast, wide differential
(FWD) SCSI bus, and an ultra–fast, wide, single–ended (UWSE)
SCSI bus. Table C–1 shows the specification differences between
these SCSI buses, and Table C–2 shows the SCSI addresses, ID num-
bers, and arbitration priorities for each.
CAUTION: Do not mix narrow, single-ended, fast, wide
differential or ultra, wide, single–ended devices
on any one bus type. Doing this will cause a
system failure.
C-3