A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such in computer networking, telecommunication equipment, and audio headsets.8P8C plug with contacts for solid wire (left) and stranded wire (right)Contacts for solid wire (top left) and stranded wire (bottom right)Pin numbering on plug. Connected pins on plug and jack have the same number. A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such in computer networking, telecommunication equipment, and audio headsets. Modular connectors were originally developed for use on specific Bell System telephone sets in the 1960s, and similar types found use for simple interconnection of customer-provided telephone subscriber premises equipment to the telephone network. The Federal Communication Commission (FCC) mandated in 1976 an interface registration system, in which they became known as registered jacks. The convenience of prior existence for designers and ease of use led to proliferation of modular connectors for many other applications. Many applications that originally used a bulkier, more expensive connector have converted to modular connectors. Probably the best known applications of modular connectors are for telephone and Ethernet.