Measuring device plug
Until the spread of digital technology, the measuring device connector was the predominant connector in the professional field of electrical communications and measurement technology. It is similar to a loudspeaker plug or a Euro plug . The pin diameter is the same, as is the spacing of the outer pins. The middle pin is attached asymmetrically, so unlike the other types, it is not possible to insert it rotated by 180 °. Despite the same pole spacing of the outer pins of 19 mm, there is no compatibility .
Occupancy:
- External contact, remote pin with a large distance to the center pin = signal or phase
- Middle contact = signal ground or return line
- External contact, close to the center contact = shielding, braided shield of the cable
The clear separation of signal ground and shielding simplifies the avoidance of earth loops . The asymmetry ensures a connection that is in phase.
The built-in socket of the measuring device plug is compatible for use with 4 mm spring clips, the most common type of banana plug .