Although the notion of social context has great appeal and is related to a family of concepts with enduring explanatory power such as thick description (Geertz, 1973), group and grid (Douglas, 1970), elaborated and restricted codes (Bern? stein, 1973) and field, tenor and code (Halliday, 1979), it remains a rather vague and mercurial concept. It would appear to reference aspects of the social psychological world of the speaker and the hearer which in addition to a mes? sage are a necessary feature of meaningful communication (see Ochs, 1979, cit? ed in Levinson, 1983: 23). Conversational analysis, which has been most speci? fically concerned to specify the work of context in producing meaningful talk, relies on rather implicit notions, although the work of Sacks includes attention to setting specific-meanings or categorizations (Sacks and Garfinkel, 1970; Sacks, 1967). The role of context is obviously crucial in organized settings which daily pro? cess a large number of calls from the public. Calls may be as brief as thirty sec? onds, provide a bare minimum of information, and yet require rapid decisions involving allocation of personnel, equipment and resources to a reported trouble. Because in police, fire and emergency services, telephone calls which omit non-verbal signs normally accompanying speech are the primary means of communication, common-sense knowledge of behaviour, along with organ? ization-specific occupational and organizational culture (Barley, 1983) is used to fill in, construct, and infer meanings. These calls and their interpretation are context-dependent communication, and their analysis should permit a further explication of the relevance of context to organizational communications. ' Organizations are formally constituted systems for the processing of com municational units utilizing set technology, a structure of roles and tasks, sys? tems of encoding and decoding meaning, and interpretative practices (see Man