Common considerations for using circular connectors
2017-11-06

All male connectors (plugs) of this family of connectors feature a 13.2 mm diameter metal shield with a notch that limits the orientation in which plug and socket can mate. A range of connectors of the same form that differ only in their pin configuration exist and have been standardized originally in DIN 41524 / IEC/DIN EN 60130-9 (3-pin at 90° and 5-pin at 45°), DIN 45322 (5-pin and 6-pin at 60°), DIN 45323 (6-pin), DIN 45329/IEC 10 (7-pin at 45°), DIN 45326 / IEC/DIN EN 60130-9 (8-pin at 45°), and other standards for a range of different applications, including the following examples:


The plugs consist of a circular shielding metal skirt protecting a number of straight round pins. The skirt is keyed to ensure that the plug is inserted with the correct orientation, and to prevent damage to the pins. The basic design also ensures that the shielding is connected between socket and plug prior to any signal path connection being made. However, as the keying is consistent across all connectors, it does not prevent incompatible connectors from mating, which can lead to damage; this is changed in Mini-DIN, which keys different connectors.


There are seven common patterns, with any number of pins from three to eight. Three different five-pin connectors exist, known as 180°, 240°, and 270° after the angle of the arc swept between the first and last pin (see figures above). There are also two variations of the six-pin, seven-pin and eight-pin connectors, one where the outer pins form 360° and one where they form 270°.There is some limited compatibility, for example a three-pin connector will fit any 180° five-pin socket, engaging three of the pins and leaving the other two unconnected, a 180° five-pin plug will fit into a seven- or eight-pin socket. 3-pin and 180° 5-pin connectors will also fit the 270° 7-pin and both 8-pin sockets. In addition to these connectors, there are also connectors with 10, 12 and 14 pins. Some high-range equipment used seven-pin connectors where the outer two carried digital system data:if the connected equipment was incompatible, the outer two pins could be unscrewed from plugs so that they fitted into standard five-pin 180° sockets without data connections.


Screw-locking versions of this connector have also been used in instrumentation, process control and professional audio.In North America this variant is often called a "small Tuchel" connector after one of the major manufacturers. Tuchel is now a division of Amphenol. The pin and socket inserts are nearly identical to those used in non-locking connectors, and in some cases locking and non-locking connectors can be mated. Additional configurations up to 24 pins are also offered in the same shell size. A bayonet-locking version was also used on portable tape recorders and dictation machines through the 1980s.