The basic purpose of CAMAC is to provide a standardized method for transferring data and control information between instrurrentation modules and a digital controller. CAMAC encompasses both a hardware standard for housing the modular components of a system and an electrical and logical standard for the control "language" used to effect the information transfer. The CAMAC specification contains the formally stated rules for hoth of these aspects of CAMAC. This paper concentrates on the control language and describes some of its features and uses in a less formal way than in the specification, and therefore may be useful as an introduction to the subject. Other papers in this series consider other aspects of CAMAC, including its place in the context of instrumentation systems, hardware aspects, signal standards, the Branch Highway, and coupling to computers and control systems. Here, the scope is limited to the process of information interchange within the CAMAC crate. This is a revised version of a paper previously publishled. Since the first version was published, a revised version of the CAMAC specification has been issued. This present paper is based only on the revised specification. Information on the differences between the original and revised CAMAC specifications is available.