The services offered by RTSE fall into three categories: association establishment, data transfer, and association termination. RT-OPEN provides for association establishment. RT-TRANSFER, RT-TURN-PLEASE, and RT-TURN-GIVE support data transfer. RT-CLOSE, RT-U-ABORT, and RT-P-ABORT provide for termination of the association. RTSE opens and closes an association by using the services of ACSE. Thus, when the Application Context includes RTSE, it is RTSE that uses ACSE.