One or more completely independent, slower, asynchronous data sources, including those from an avionics subsystem, a serial output, a computer, or a video sensor, can be merged with the main telemetry stream to form an embedded asynchronous data stream (EADS). These embedded streams include overhead and synchronization words and are inserted into reserved words in the main frame. The embedded asynchronous data stream is a completely independent major frame and includes frame and subframe sync words. Each EADS word can be a discrete binary, octal, decimal, or hexadecimal format. CRC words can also be sent in the minor frame word along with flags for stale data (new data not present when required by the encoder) and overflow data (more data available than allowed for in the main frame). Since the EADS’ embedded frame data rate is asynchronous to the minor frame, there is a chance that either more data is available than can fit in the EADS, with resultant data loss, or that there is insufficient data available to fill the frame.

The term asynchronous is used with respect to the appearance of the EADS’ sync words. The EADS frame sync moves in time among the EADS words. This is the case in a frame with multiple EADS word locations where frame lengths are not even multiples of each other. The main frame may also be designed such that the main encoder is either in word synchrony with the EADS stream or that filler words are added when real data is not yet present (the ground system will need to remove this extraneous data).

At the ground station, a hardware decommutator extracts and directs the EADS words to an independent hardware decom for decommutation. Multiple independent EADSs can be supported by one main stream. Each of the streams is sent to its own decommutator. In theory, each EADS could have its own EADS, but in reality, this low sample rate is not seen. If the EADS is a much slower stream than the main stream, decommutation can be accomplished by a "software decom" in a front-end real-time processor or workstation. The IRIG-106 Standard indicates a maximum of two independent EADSs per major stream.

The example below requires transmission of 11 major frames to receive two EADS frames (assuming that the word lengths of both frames are identical). This is not a constraint for the EADS word in the main frame; it is just a series of bits in the embedded stream.

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