The concept of a telephone interpreting service is straightforward and simple: when two people cannot understand each other as a result of language differences they phone a central office which then telephonically links them to an interpreter. The application of the concept is more complicated, owing to the technology, costs, and organisation needed for such a service. Besides discussing the aim, objectives and outcomes of a full national telephone interpreting service, the article enters into the scope of the service in Australia and South Africa, interpreting for the deaf, etc.