What is a D-Sub?
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D-sub (short for D-subminiature) is a connector used for a wide variety of
purposes with computers and other electrical equipment. The "D" of the title
refers to the shape of the metal shield of the connector. The shield roughly
looks like a "D" rotated 90 degrees to the right. The "miniature" of the title
refers to the outdated fact that the D-sub, at the time of its release in the
early 1950s, was basically the smallest common connector. Today, they are among
the largest connectors, but it is remarkable that they are still commonly used
after more than 50 years.
The D-shaped electromagnetic shield is held in place by two
fastening screws. The shield surrounds rows of pins or sockets. The number of
rows and the number of contacts in each varies with the type of D-sub connector.
Cannon has standardized an abbreviated naming system to denote the physical
architecture of the D-sub connector. The name of a D-sub connector will look
something like this: DE-9P. The name will always begin with a "D" which
marks it as a D-sub connector. The next letter, A-E, refers to the size of the
shell (see illustration). The number refers to the number of pins or sockets.
And the "P" or "S" at the end refers to whether the connector has pins (male) or
sockets (female).
| D |
Always "D" to designate D-subminiature (sometimes HD or DD,
depending on density) |
| E |
A,B,C,D, or E to designate shield size. Shields A-D grow increasingly larger,but
E is smallest |
| - |
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| 9 |
The number of pins ranges between 9 to 100. See following paragraph and table
for more information |
| P |
"P"ins (male) or "S"ockets (female) |
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The number of pins within a certain shield size is
standardized between three variables depending on whether the connector is normal
density, high density, or double density. Ishmael Stefanov Wagner has the
following handy table on his D-Subminiature Nomenclature webpage. This table shows the number of pins
in each D-Sub shell type:
| Shell |
2-Row |
3-Row (High Density) |
Double Density |
| DE |
9 |
15 |
19 |
| DA |
15 |
26 |
31 |
| DB |
25 |
44 |
52 |
| DC |
37 |
62 |
79 |
| DD |
50 (3 rows) |
78 (4 rows) |
100 (4 rows) |
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Applications/Usages
D-Sub connectors have a wide variety of uses, but many of these
uses are being superseded by new technology. Here are a few examples of uses
that still remain common:
- Among desktop computers, the HD-15 VGA connector is standard for connecting monitors and CPUs.
- DB-25, and later DE-9, cables are most commonly used for computer serial connectivity. Examples include: DB-25 parallel printer cables, DE-9 serial cables used for early peripheral connectivity (PDAs, digital cameras, etc.), and DE-15 VGA display cables. As most mobile devices and computer peripherals now utilize USB and/or FireWire for serial connectivity, D-sub connectors are becoming more expensive and rarer on mainstream consumer computers.
- Uses for uncommon D-sub connectors include DA-15 analog joystick connectors (“game ports” on PCs), DA-19 for Apple II external floppy drive connectivity, and DA-23 for the Commodore Amiga's video output/external floppy drive.
- DB-25 connectors were also used in the professional recording and broadcasting industries.
Practical Info
- The maximum practical length for a single D-sub cable is often 100 feet. Extension possibilities include male/male, male/female, and female/female cables of up to 100 additional feet.
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