SCSI Connectors and SCSI Cable information
SCSI Terms, SCSI specifications - SCSI cable length specs
The Connectors:
IDC50
50 Pin Header
IDC50 Female
IDC50 Male
IDC 50 pin female, mates to IDC50 male "header", used on SCSI-1, SCSI-2, Ultra SCSI "narrow" etc. All internal 50-conductor "8-bit" SCSI uses these cconnectors.
CN50
CN50 Male
CN50 Female
Centronics C50 sometimes referred to as CN50, Cent50 (External connector on many SCSI-1 and some SCSI-2 Controllers) The controller connector and peripherals connectors should be females, and the cables male.
DB25
DB25 Male
SCSI-1
Used with the older Macs, Zip drives, and many scanners.
DB25 Female
HD50
HD50 Male
(Mini D50 HPDB50 SCSI-2/SCSI-3 external connector) . The easy way to tell the difference between an HD50 and an HD68 (unless you want to count those tiny little pins) is to measure them. HPDB50 is about 1 3/8” (36mm) , and the HPDB68 is about 1 7/8” (47mm)
HD50 Female
HD68
HD68 Male
(MiniD68 HPDB68 Ultra wide SCSI-3/ Ultra2 LVD SCSI/ wide Differential SCSI both internal and external) The internal and external connectors appear to be different, but they are the same basic connector. The easy way to tell the difference between an HD50 and an HD68 (unless you want to count those tiny little pins) is to measure them. HD50 is about 1 3/8” (36mm) , and the HD68 is about 1 7/8” (47mm).
HD68 Female
VHDCI
VHDCI male
VHDCI 0.8mm HPCN68 male- Sometimes called SCSI-5. Very popular in RAID cards.
VHDCI female
HDI-30
HDI-30 is for Apple Macintosh PowerBooks.
HPCN50
Used in Japan, on several Digital cameras and things.
HPCN50 pin (rare)
DB50
DB50 Male
SCSI-1
Usually used on old Sun Sparcstations.
DB50 Female
DB37
Male DB37
SCSI-1
Female DB37
HDCN60
(Mini Centronics 60 HDCN60 - old IBM RS6000)
We don't carry these cables anymore
The SCSI Types Bus lengths, devices supported, etc.
Much more info on SCSI Cable lengths and "gotchas" below the chart
STA (SCSI Trade Association) -Endorsed Terms & Terminology for SCSI Parallel Interface Technology.
see here for term descriptions
STA
Terms
(notes-see below)
|
Bus Speed, MBytes/Sec.
Max. |
Bus Width, bits |
Max.
Bus Lengths, Meters (1) |
Max. Device Support |
Single-
ended |
LVD |
HVD |
| SCSI-1(2) |
5 |
8 |
6 |
(3) |
25 |
8 |
Fast
SCSI (2) |
10 |
8 |
3 |
(3) |
25 |
8 |
Fast
Wide SCSI |
20 |
16 |
3 |
(3) |
25 |
16 |
Ultra
SCSI (2) |
20 |
8 |
1.5 |
(3) |
25 |
8 |
Ultra
SCSI (2) |
20 |
8 |
3 |
- |
- |
4 |
Wide
Ultra SCSI |
40 |
16 |
- |
(3) |
25 |
16 |
Wide
Ultra SCSI |
40 |
16 |
1.5 |
- |
- |
8 |
Wide
Ultra SCSI |
40 |
16 |
3 |
- |
- |
4 |
Ultra2
SCSI (2,4) |
40 |
8 |
(4) |
12 |
25 |
8 |
Wide
Ultra2 SCSI (4) |
80 |
16 |
(4) |
12 |
25 |
16 |
Ultra3
SCSI or Ultra160 SCSI (6) |
160 |
16 |
(4) |
12 |
(5) |
16 |
| Ultra320 SCSI (6) |
320 |
16 |
(4) |
12 |
( |
|
Notes:
- The listed maximum bus lengths may be exceeded in Point-to-Point and engineered applications.
- Use of the word "Narrow", preceding SCSI, Ultra SCSI, or Ultra2 SCSI is optional.
- LVD was not defined in the original SCSI standards for this speed. If all devices on the bus support LVD, then 12-meters operation is possible at this speed. However, if any device on the bus is singled-ended only, then the entire bus switches to single-ended mode and the distances in the single-ended column apply.
- Single-ended is not defined for speeds beyond Ultra.
- HVD (Differential) is not defined for speeds beyond Ultra2.
- After Ultra2 all new speeds are wide only.
The Cable Length Rules*
(In case you're not confused yet)
A short simplified guide to scsi cable lengths.
|
Type
of SCSI
|
"Single-ended"
(Regular) SCSI bus length
|
"Differential"
SCSI bus length
|
LVD
SCSI bus length ††
(ULTRA2 OR ULTRA160)
|
|
5
MHz (SCSI-1)
|
6
meters
|
25
meters
|
-
|
|
10
MHz (SCSI-2 FAST, Fast / Wide SCSI)
|
3
meters
|
25
meters
|
-
|
|
20
MHz (Ultra SCSI, Ultra Wide SCSI or "Fast20")
|
3
meters (3 devices + host adapter) or 1.5 meters (4 devices + host adapter)*
|
25
meters
|
-
|
|
40
MHz (Ultra2,Ultra160, U320 SCSI or "Fast40")
|
-
|
-
|
12
meters
|
*please note: "Ultra" SCSI cable lengths
are severely limited! The maximum cable
length is ten feet when four devices (including the host adapter) or less are on the bus. If five devices are used (four
devices and your host adapter), then the maximum bus length is 1.5 meters
(five feet!). ††Knocking
Ultra2 or U160 chains out of LVD mode by putting "Legacy" Single
Ended (regular Ultra scsi, etc) devices on the chain
will give you the same cable length restrictions as Ultra scsi. Watch
it!!
|
