An intelligent high performance host interface to a Cambridge ring local area network

The MACE (modular access to computer equipment) is an intelligent front-end communications device designed to interface general-purpose computers to a high speed local area network (LAN). Considerable care has been taken to define external interfaces, both upper and lower, which are largely independent of the details of both the attached host computer system and the supporting communications techniques. The implementation described incorporates the necessary low level protocol handling in a combination of hardware and software for attachment to a slotted Cambridge Ring. The same techniques could, however, also be readily applied to interface to other LAN technologies. The principles of operation and design objectives are described, together with some details of the hardware and software implementation features which are combined to produce a general high performance communications facility.