The operating support systems such as CSMS, TLMOS, and SLMOS may be related each other. At the present time, UNIX system is most popular operating system. TLMOS and SLMOS have been developed under the UNIX environment and using C language. On the other hand CSMS was built on HP RTE O. S. using Pascal. When we constuct the operation and maintenance organization by networking several operations support system, the interface of intersystem must be simple and the integrity of whole system must be kept. It is somewhat valuable to investigate transfering CSMS from RTE O. S. to UNIX in order to integrate operations and maintenance systems. Here, we give a basic material about porting CSMS in UNIX