D-Subminiature Nomenclature

Having seen too many references to a "DB-9" connector, I have compiled the following information in the hope that it might make for more accurate discourse. For all the projects that call for a "DB-9", and distributors that offer to sell them, there is not one manufacturer that I have found who actually makes such an item.

D-Subminiature connectors appear in several families; normal, with approximately 0.108 inch pin spacing, high-density, double-density, and combination arrangements.

Shell sizes

For the past few decades there have been five standard shell sizes, DA, DB, DC, DD, and DE, which can accomodate various number of contact pins. The following table shows pin counts for both normal and high-density D-Sub connectors for various shell sizes.

D-Subminiature connectors
shell   2-row  3-row (hi-Dens) Double-Density
 DE-     9     15              19
 DA-    15     26              31
 DB-    25     44              52
 DC-    37     62              79
 DD-    50(3r) 78(4r)         100 (4 row)

There are also the combination connectors, which trade off some number of regular pins to fit in larger coaxial, high current, or high voltage contacts.

Conclusion

The specified RS-232 terminal connector is a DB-25, the PC parallel port connector is also; the serial/mouse port on a PC may take a DE-9, but most emphatically not a DB-9. Note also that there are two different 15-pin connectors in common use, the DA-15 (standard) and DE-15 (high-density). Calling it a DB-15 is not only incorrect, but is ambiguous.

Examples

Standard
Specified connector for RS-232 is DB-25; with a DB-25P (male) on Data Terminal Equipment (DTE) and DB-25S (female) on Data Communications Equipment (DCE); where DTE is most commonly a terminal, and DCE a modem.
Video output connectors from Macintosh Nu-bus computers is via a DA-15 socket.
High-Density
The current contemporary SVGA connector is a high-density DE-15.
Combination
A large color monitor in the next room has a B-size shell with 10 regular (#20) pins plus three coaxial contacts for the RGB signals, ITT/Cannon part DB-13W3.

See also ePanorama on D-Subminiature Connectors which gives examples of commonly used parts.
Cinch D-Subminiature catalog page.

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Original 18 October 1999
Last modified: Dec 26 13:20 2001 / Ishmael Stefanov-Wagner