- Centronics 50 Male to HP68 (Half Pitch 68) Male
Centronics 50 Male - At one time this was one of the most common SCSI connectors. Used for scsi-1 applications:
older scanners, controllers, external scsi device cases.
The Centronics 50 connector has 50-pins arranged in two rows one on top of the other.
The top row has 25 pins and the lower row has 25 pins. Used mostly with older 5 MB SCSI-1
Systems. Often called Low-Density SCSI-1 connector. Most SCSI SLOW (5 Mbyte/sec) computers
and host adapters use the Centronics type 50-pin connector. Also some 8-bit Fast computers
and host adapters.
HP68 Male - Probably the most common SCSI connector used today. Used on all SCSI Wide applications and some old DEC single-ended SCSI
this connector provides a highly secure connection. Used for scsi-3 applications: scanner, removable
storage drive, controller, external cdr/cdrw, ultra/2. The HP68 connector has
68-pins arranged in two rows one on top of the other. The top row has 34 pins and
the lower row has 34 pins.
- SCSI 1 to SCSI 3
- SCSI 1 - The original standard that was derived from SASI and formally adopted in 1986 by ANSI.
SCSI-1 features an 8-bit bus (with parity), running asynchronously at 3.5 MB/s or 5 MB/s
in synchronous mode, and a maximum bus cable length of 6 meters (just under 20 feet --
compare that to the 18 inch (0.45 meter) limit of the ATA interface). A variation on the
original standard included a high-voltage differential (HVD) implementation whose maximum
cable length was many times that of the single-ended versions.
- SCSI 3 - Before Adaptec and later SCSITA codified the terminology, the first parallel SCSI devices
that exceeded the SCSI-2 capabilities were simply designated SCSI-3. These devices, also
known as Ultra SCSI and fast-20 SCSI, were introduced in 1992. The bus speed doubled again
to 20 MB/s for narrow (8 bit) systems and 40 MB/s for wide. The maximum cable length
stayed at 3 meters but ultra SCSI developed an undeserved reputation for extreme sensitivity
to cable length and condition (faulty cables, connectors or terminators were often to
blame for instability problems).