Codeblock the protocol data unit of the tc coding

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Unformatted text preview: TC Coding layer. CODEBLOCK: The protocol data unit of the TC Coding layer. A TC Codeblock contains the encoded symbol representation of a small set of contiguous TC information bits. CODING LAYER: The upper layer of the TC Channel Service. COMMAND: An instruction sent from a user to a receiving application process in space in order to effect a change in that process. COMMAND DIRECTIVE: A machine-interpretable representation of a user-desired command action. Issue 6 Page A-3 January 1987 CCSDS REPORT CONCERNING TELECOMMAND: SUMMARY OF CONCEPT AND SERVICE COMMAND LINK CONTROL WORD: The TC Transfer layer protocol data unit for telecommand reporting, which is embedded in the trailer of a CCSDS Telemetry Transfer Frame. It conveys status information from the receiving end to the sending end of the TC Transfer layer. COMMAND LINK TRANSMISSION UNIT: Within the Coding layer, the protocol data unit which carries buffers of error-protected symbols (corresponding to one or more encoded Telecommand Transfer Frames) during transfer through the data channel to the spacecraft. COMMAND OPERATION PROCEDURE (COP): A sequence of procedural activities designed to assure the reliable, error-controlled delivery of Telecommand Transfer Frames. Each COP comprises a Frame Operation Procedure operating within the sending end and a Frame Acceptance and Reporting Mechanism operating within the receiving end. CONTROL COMMAND: A special, dedicated TC Transfer Frame containing control information to set up the receiving parameters of the spacecraft end of the TC Transfer layer. CONTROL INSTRUCTION: A data object which is passed between layers within the TC System in order to set up the parameters of data transfer. DATA MANAGEMENT SERVICE: In the space data systems layered telecommand architecture, the top service of the Telecommand System. It includes the primary facilities for interfacing the user with the systems used to communicate telecommands. Its bottom layer provides a protocol data unit known as a Telecommand Packet, which provides data formatting services so that command data may be transported between user application processes. DATA ROUTING SERVICE: In the space data systems layered telecommand architecture, the middle service of the Telecommand System. It provides a fundamental service within the TC System by guaranteeing the delivery of TC data from the sending to the receiving ends of the ground-tospace data link. Issue 6 Page A-4 January 1987 CCSDS REPORT CONCERNING TELECOMMAND: SUMMARY OF CONCEPT AND SERVICE DELIVERY: The process of passing transported telecommand data across the interface to the Application Process layer at the receiving end of the TC System. DELIVERY CONDITIONS: Control instructions, generated by the Application Process layer, which specify the parameters and conditions that are required to exist within lower layers in order to perform the delivery of telecommands from the sending to the receiving end of the TC System. EXECUTION: The act of effecting a commanded change within a spacecraft application process, in response to a telecommand which has been delivered to that pr...
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