A ribbon cable is a cable with many conducting wires running parallel to each other on the same flat plane. As a result, the cable is wide and flat. Its name comes from its resemblance to a piece of ribbon.
Ribbon cables are usually seen for internal peripherals in computers, such as hard drives, CD drives and floppy drives. On some older computer systems (such as the BBC Micro and Apple II series) they were used for external connections as well. The ribbon-like shape interferes with computer cooling by disrupting airflow within the case and also makes the cables awkward to handle, especially when there are a lot of them; as a result, round cables have almost entirely replaced ribbon cables for external connections and are increasingly being used internally as well.
The original form of ribbon cable was two-conductor 300 ohm twin lead cable used for radio and television, which is also called "ribbon cable". However the more modern forms more commonly called "ribbon cable" typically have many more than just two conductors.
Many-wire ribbon cable was invented in 1956 by Cicoil Corporation, a company based in Chatsworth, California. The company's engineers figured out how to use a new material, silicone rubber, to 'mold' a flat cable containing multiple conductors of the same size. Since the cable looked like a flat ribbon or duct tape, it was named a ribbon cable. The ribbon cable allowed companies like IBM and Sperry / Univac to replace bulky, stiff round cables with sleek, flexible ribbon cables.
The early ribbon cables were used in the mainframe computer industry, on card readers, card punching machines, and tape machines. Subsequently, ribbon cables were manufactured by a number of different companies, including 3M. Methods and materials were developed to simplify and reduce the cost of ribbon cables, by standardizing the design and spacing of the wires, and the thickness of the insulation, so that they could be easily terminated through the use of insulation-displacement connectors (IDC). The simplicity of the cables, their low profile (compared to contemporary alternatives), and low cost due to standardization, meant ribbon cables were long used in computers, printers, and many electronic devices.
