A pioneering high-speed local area network, originally developed at Cambridge University, UK. It used a minipacket of 40 bits: 16 bits held 2 bytes of data, two groups of 8 bits specified the addresses of the source and destination nodes, and the remaining 8 bits were used for control purposes. A master station controlled the inter-bit time and the gap between packets, so that the ring circulated an exact number of packets and gaps. Each packet contained a single-bit indicator as to whether it was full (i.e. the packet contained useful data) or empty (i.e. the packet data had been received by the destination node, and the packet had completed a circuit of the ring back to the original source node). The Cambridge Ring was thus an example of an “empty slot” ring. See also token ring.