The purpose of this document is to define the Space Link Extension (SLE) Return Operational Control Fields (ROCF) service in conformance with the SLE Reference Model (reference [1]).° The ROCF service is an SLE transfer service that delivers to a mission user all operational control fields from one master channel or one virtual channel.

This document defines, in an abstract manner, the ROCF service in terms of:

1. the operations necessary to provide the service;
2. the parameter data associated with each operation;
3. the behaviors that result from the invocation of each operation; and
4. the relationship between, and the valid sequence of, the operations and resulting behaviors.

It does not specify:

1. individual implementations or products;
2. the implementation of entities or interfaces within real systems;
3. the methods or technologies required to acquire telemetry frames from signals received from a spacecraft;
4. the methods or technologies required to provide a suitable environment for communications; or
5. the management activities required to schedule, configure, and control the ROCF service.

NOTE°° °°°°°° Reference [1] defines the Return Master Channel Operational Control Field (Rtn MC-OCF) service and the Return Virtual Channel Operational Control Field (Rtn VC-OCF) service as two distinct services. Subsequent study has indicated that it is preferable to define one service that provides the functionality of both. The ROCF service defined here does just that. It is anticipated that a future issue of reference [1] will take the same approach, deleting the Rtn MC-OCF and Rtn VC-OCF services and replacing them with the Rtn OCF service.