4Piin

4Piin is a term used in electronics to denote a four-pin input/output interface and the associated connector family used in various devices and hobbyist kits. It is not a formal IEC/IEEE standard; rather, it appears in product documentation and educational materials as a shorthand for a simple four-pin scheme. The name reflects the four conductors and the notion of an “in” or input/output channel arrangement.

Typical 4Piin assemblies consist of four conductors in a compact housing with polarized or keyed mating halves to prevent incorrect mating. A common pinout allocates power (Vcc) and ground (GND) plus two signal lines for data or control. Pin pitch commonly ranges from about 2.0 to 2.54 mm; contacts are often crimped or soldered and may include locking features to improve retention in vibration-prone environments.

Signaling and protocols under the 4Piin label vary, as there is no universal standard. Implementations range from simple DC power with a single control line to more complex serial options such as UART, I2C-like communication, or PWM control, depending on device requirements. Some vendors supply compatible 4Piin cables and headers for their product lines, but cross-vendor compatibility is not guaranteed without a defined mating standard.

Applications for 4Piin are common in educational electronics kits, small robotics projects, LED lighting modules, and general prototyping where a compact four-pin interface suffices. It may also appear in consumer devices for accessory connections or low-power sensors.

See also: 4-pin connectors; JST and Molex 4-pin families; UART; I2C.