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SCSI Connector Guide
This info will help you determine which data interface cable
to choose to put between your devices in a daisy chain or to put between the
storage device/peripheral and the host adapter that is in your computer. Also
this can help us all to communicate better when it comes to which connector you
want on your device(s), cable(s) or adapter(s)/controller(s). As you can see
some connectors go by several different names. Pictures are not to
scale.
Connector Type or Name: IDC50
50 pin
insulation displacement connector (IDC) used on cables (the female connector is
used on cables) for internal cabling
and male connector is used on
storage device or host adapters. SCSI-1, SCSI-2, Ultra SCSI, "Narrow", 8 bit
devices, use this "low density 50-pin" connector.
IDC50 Female Connector (on cable
sides)
IDC50 Male Connector (on device or adapter side)
Connector
Type or Name: CN50
Centronics 50-pin C50, CN50, Cent50, was at one time
the most popular way to connect external SCSI devices mostly with 5MB
SCSI-1 and 10MB SCSI-2 systems. The controller/adapter connectors and
peripheral connections should be female while the cable ends should be male.
According to Adaptec this is "low density 50-pin'.
Centronics CN50 Male Connector (on cable
sides)
Centronics CN50 Female Connector (on device & adapter
side)
Connector Type or Name: HD50 High
Density 50-Pin
Called Mini D50, MicroDB50, MiniDB50, most 8-Bit
SCSI FAST (up to 10MB/sec) host adapters use this "high density 50-pin"
connector. 50-pin HD50 connector is 1 3/8" (36mm) wide vs. 1 7/8" (47mm) wide
for a 68-pin HD68 connector. Used on SCSI-2 and SCSI-3 peripherals.
HD50 Male Connector (on
cable
sides)
HD50 Female Connector (on device or adapter side)
Connector
Type or Name: HD68 High Density 68-Pin
Called MiniD68,
HD68, MicroDB68, MiniDB68, 68-Pin Micro D, are the most common SCSI
connectors used today. Used with Ultra Wide SCSI-3, Ultra2 LVD SCSI, Wide
Differential SCSI devices. This 68-pin connector is 47mm or 1 7/8 inches wide.
HD68 Male Connector (on
cable
sides)
HD68 Female Connector (on device or adapter side)
Connector
Type or Name: VHDC1 Very High Density Condensed 68-Pin
Called .08, Ultra
Micro DB68, Ultra High Density, is used with many RAID cards.
VHDC1 Male
Connector
VHDC1 Female
Connector
Connector Type or Name: SCA
Called SCA, SCA-2,
(Single Connect Attachment), this 80-pin connector has extra pins used to
provide
power for hot swap drives.
SCA Female Connector (on device
side)
Connector
Type or Name: DB25 Male SCSI-1
Used with the older Macs, Zip drives, and many scanners.
DB25 Male
DB25 Female
STA-Endorsed Terms & Terminology for SCSI
|
|
STA Terms |
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 |
(5) |
16 |
| |
Notes:
(1) The listed maximum bus lengths may be exceeded
in Point-to-Point and engineered applications.
(2) Use of the word "Narrow", preceding SCSI, Ultra
SCSI, or Ultra2 SCSI is optional.
(3) 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.
(4) Single-ended is not defined for speeds beyond
Ultra.
(5) HVD (Differential) is not defined for speeds
beyond Ultra2.
(6) After Ultra2 all new speeds are wide
only.
SCSI Terms - STA
overview of the different SCSI Standards and
Cables. |
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