 can bus (for controller area network) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer. can bus is a message-based protocol, designed specifically for automotive applications but now also used in other areas such as aerospace, maritime, railway vehicles, industrial automation and medical equipment. development of the can bus started originally in 1983 at robert bosch gmbh. the protocol was officially released in 1986 at the society of automotive engineers (sae) congress in detroit, michigan. the first can controller chips, produced by intel and philips, came on the market in 1987. bosch published several versions of the can specification and the latest is can 2.0 published in 1991. this specification has two parts; part a is for the standard format with an 11-bit identifier, and part b is for the extended format with a 29-bit identifier. a can device that uses 11-bit identifiers is commonly called can 2.0a and a can device that uses 29-bit identifiers is commonly called can 2.0b. these standards are freely available from bosch along with other specifications and white papers.bosch semiconductor can literature in 1993 the international organization for standardization released the can standard iso 11898 which was later restructured into two parts; iso 11898-1 which covers the data link layer, and iso 11898-2 which covers the can physical layer for high-speed can. iso 11898-3 was released later and covers the can physical layer for low-speed, fault-tolerant can. the physical layer standards iso 11898-2 and iso 11898-3 are not part of the bosch can 2.0 specification. these standards may be purchased from the international organization for standardization (iso).international organization for standardization can in automation (cia) also published can standards; can specification 2.0 part a and part b, but their status is now obsolete (substituted by iso 11898-1).can in automation (cia) other specifications bosch is still active in extending the can standards. in 2012 bosch released can fd 1.0 or can with flexible data-rate. this specification uses a different frame format that allows a different data length as well as optionally switching to a faster bit rate after the arbitration is decided. can fd is compatible with existing can 2.0 networks so new can fd devices can coexist on the same network with existing can devices. can bus is one of five protocols used in the on-board diagnostics (obd)-ii vehicle dia
Automation Computer_networks Industrial_automation Industrial_computing Serial_buses