20pin

20pin, sometimes written as 20-pin, is a generic term for an electrical connector or header that has twenty contact pins. The designation spans multiple connector families and form factors, so the exact mechanical shape, pitch, and pinout vary by standard and manufacturer. Because there is no single universal 20pin standard, devices with a 20pin connector are not automatically interchangeable without checking the specific pin arrangement.

A widely known example is the 20-pin ATX main power connector used on older desktop motherboards. This two-row arrangement carries multiple power rails and ground from the power supply. With the later introduction of the 24-pin ATX standard, many systems retained the 20pin portion for compatibility, sometimes in combination with a separate 4-pin 12V connector for CPU power. This illustrates how 20pin form factors can coexist with newer standards.

Beyond power connections, 20pin headers and connectors are common for internal signals in electronics. They appear in IDC ribbon-header families and in development and debugging interfaces, such as JTAG, which often use 20pin, 0.1-inch (2.54 mm) pitch headers with various pinouts depending on the device or board vendor.

Users should consult device documentation when mating a 20pin component with another system. The pinout is device-specific, and incorrect connections can cause damage. In summary, 20pin denotes pin count rather than a single, universal standard, and its practical meaning depends on the specific connector family and application.