This paper details concurrent object oriented switching program with the following aspects that improve program maintainability and extendability. This program is structured as a direct mapping of a logical switching system model, mapping each logical component to a software "object". Concurrent objects are introduced for multi-processing, and sequential objects are introduced to efficiently implement objects that need no concurrency. Switching programs must meet the very severe requirements of real-time multi-processing services, but the existing objectoriented programming languages have insufficient efficiency and concurrency. Because of this, concurrent object-oriented programming has been devised for Chill (CCITT recommended language) and a simple preprocessor can be used to enhance its writability and readability.