The paper describes Comflex, a packet switching node intended to provide local computer-to-computer and computer-to-peripheral communication. It has been developed as part of the Flex distributed computer system being produced at RSRE. Comflex is capable of transmitting data at magnetic-disc speed; hence, it makes feasible the use of remote file-stores (and other peripherals) in a local network. High performance is achieved by implementing the most important control algorithm in hardware (unlike conventional packet switches, which are controlled by software). The paper describes the design of Comflex and the major influences it has on the overall system design and operation.