Doxy,
The Wirek Wire recorder issued to me as a 20 year old in 1948 recorded data DIGITALLY on a long steel wire. It couldn't do anything else, just ON or NOT ON..... It was the size of a small suitcase - but heavier.
Some 30 years later, my employers had their B707 Flight plans prepared at JFK ( or was it Idlewild ?) and telexed, digitally to the UK.
My very own ZX81 battery powered computer from 1982, recorded digitally on cassette tapes. (I learned just a little binary, too !) I saw one used with a digital camera (B&W) a year or two later.
Once data is recorded digitally, surely the use of a checksum tended to prevent or at least identify possible errors.