Cables are insulated assemblies of copper or optic fiber terminated by connectors. They are available in many configurations including ribbon, power line, video, audio, coaxial, high-speed serial and many special purpose cable assemblies (harnesses). Fiber optic cables are also available for high-speed data communications. Cabling can integrate a conductor shielding layer for EMI suppression. High speed data cables can have differential pairs that may be twisted together for additional suppression and common mode rejection. They can also incorporate additional guard layers for strength. Cables with connectors attached are said to be cable assemblies.
Ribbon cables are typically flat flex cables with multiple conductors. They may have connectors attached, or may have a strengthened edge with an exposed wire strip for insertion to a board connector. Power cables comprise of thicker wires with high current carrying capability, may have several connections for multiple voltage rails and may be accompanied by signaling, sensing or control wires. An example of this is the Molex connector used in computer power supplies. Video cables consist of several impedance matched insulated conductors in an insulated and shielded sheaf and usually sold as assemblies. Examples include HDMI and DVI cables.
Mono or stereo phone plugs, bantam plugs, RCA connectors, DIN plugs and standard telephone connectors usually terminate audio cables. They are typically shielded, robust assemblies with high quality connector options. Coaxial cables are typically used in high frequency RF applications. They typically have 50 or 75 Ohm characteristic impedance, are terminated with RF connectors like BNC, SMA, TNC or N types. Teflon and semi-rigid coaxial varieties are available for high power and high frequency applications. These can also be seen as circuit elements in RF designs. Examples of this include quarter wave sections, splitters, combiners and directional couplers.
High-speed serial cables are available to support standards like: Ethernet, SATA, Thunderbolt, Firewire and USB (in all its versions). These typically comprise of matched differential pairs that are shielded and fall within the length constraints specified in the applicable interface standard. Some cables support “power over” the cable to the remote device. Examples of this include various USB configurations and Power over Ethernet (POE). Fiber optic cables are constructed of flexible transparent drawn silica thinner than a human hair. They transmit light over long distances and have the advantage of EMI immunity.