dualinline

Dual inline refers to packaging and connector arrangements that place electrical contacts in two parallel rows. The term is most often used for dual inline packages (DIPs) used to package integrated circuits, and for dual inline memory modules (DIMMs) used to house computer memory. In both cases the defining feature is symmetry of contacts on opposing sides.

Dual inline package: The DIP is a through-hole IC package with a rectangular body and pins that extend from the bottom along two opposite sides. Pins are spaced 2.54 mm (0.1 in) apart in each row, and the two rows are separated by a defined body width (narrow around 0.3 in; wide around 0.6 in). Pin counts range from a few to several dozen. The package is designed for insertion into through-hole PCB pads or into a DIP socket. DIP devices were widely used in early microprocessors, TTL logic, and memory, and remain common in hobbyist and repair work.

Dual inline memory module: A DIMM is a small PCB carrying memory chips and an edge connector with two rows of contact pads along the bottom edge. The notch on the module ensures correct orientation. DIMMs are available in several generations (for example DDR, DDR2, DDR3, DDR4, DDR5) with pin counts that have increased over time (commonly 240 pins for DDR2/DDR3, 288 pins for DDR4/DDR5). DIMMs plug into corresponding motherboard sockets and are a standard for desktop and server memory.

See also: Dual inline package, DIMM.