Version Number for this message content description Receiver, device, point, path, etc. where data was received. Used to distinguish data simultaneously received at multiple collection points. Identifies the kind or source of the stream of telemetry as either Real-time, Replay, Simulator, or Test. When true (and known, especially for replay data), indicates the last message in the stream. Length of frame Time of frame, usually ground receipt time State of frame synchronization from equipment when frame is ingested Raw telemetry data