What Is X.25?

X.25 seems like something out of a science lab that is used in evil ways, but it's actually not. It is for your computer, and it makes your work easy and effortless. Want to know more? Here goes, it is the oldest but the best packet-switching technique available and was commonly used before the Open System Interconnection (OSI) reference model became standard. The X.25 protocol suite was defined by the International Telegraph and Telephone Consultative Committee in 1976, initially to carry voice signals over analog telephone lines. X.25's name comes from its designation in ITU Recommendation X.25, which defines a set of procedures for data transmission between two systems over a telecommunication network. Initially developed for use in the 1970s and used widely in the 1980s, X.25 has since fallen out of favor, having been replaced by less complex protocols such as Internet Protocol (IP). X.25 is a packet-switching network protocol that works at the network's physical side of the data link and network layers. The X.25 protocol covers such tasks as packet assembly at the source, delivery and disassembly at the destination, error-checking and retransmission in case of errors. X.25 devices fall into three common categories, Packet-switching exchange: A device that essentially and quickly provides the customers with access to an X.25 packet-switched network from a dialup line or leased line, also known as a packet switch or gateway. Data circuit-terminating equipment: A device used by telecom operators for providing connections between networks, also known as DTE (data terminal equipment). Data terminal equipment: A device used by customers for accessing an X.25 packet-switched network over a dedicated line, also known as DCE (data communications equipment). Today, it is mainly relegated to ATM machine systems and credit card verification networks.