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Many of the control codes are still in active use today in the air-ground communications protocol spoken between airplanes and Air Traffic Control. The ACARS[0
by coderjames 10y ago
Many of the control codes are still in active use today in the air-ground communications protocol spoken between airplanes and Air Traffic Control.
The ACARS[0] protocol I work with every day starts each transmission with an SOH, then some header data, then an STX to start the payload, then ends with either an ETX or an ETB depending on whether the original payload had to be fragmented into multiple transmissions or fits entirely into one.
These codes aren't archaic and obsolete in the embedded avionics world.
[0] ACARS: "Aircraft Communications Addressing and Reporting System" - see ARINC specification 618[1]
[1]http://standards.globalspec.com/std/10037836/arinc-618 http://standards.globalspec.com/std/10037836/arinc-618
- Animats 10y agoHere's the origin of that - The Teletype Model 28 "stunt box".[1] This was a mechanical state machine, programmable by adding and removing metal levers with tines that could be broken off to encode bit patterns. These were used in early systems where a central computer polled mechanical Teletype machines in the field, and started and stopped their paper tape readers and other devices. Remote stations would punch a query on paper tape and put it in the reader, then wait until the central computer would poll them and read their tape. This was addressable, so many machines could be on the same circuit. Used in 1950s to 1970s, when mainframes were available but small computers were not. [1] https://www.smecc.org/teleprinters/28stuntbox001.pdf https://www.smecc.org/teleprinters/28stuntbox001.pdf
- i336_ 10y agoThanks so much for sharing this. This is exactly the kind of TTY history I've always been looking for.