In 1957, Western Union telegraph facilities were used to transmit remote data to computers for processing. Teleprinter terminals were also used for interactive processing. Because of the amount of critical numerical information transmitted, transmission errors had to be found and corrected. (AT&T was also doing reearch into this, discussed previously in this newsgroup).
The basic telegraph Baudot transmission code did not have provisions for error checking. Various methods were used to detect errors, such as a hash total at the end of a block of characters.
While we take error correction for granted these days, it remains a key part of data transmission, even if it is transparent to most of us. An article in the January 1957 Western Union Technical Review describes their pioneer data transmission and error detection efforts.
Very early on, punched cards were fed into a machine that converted the data into a Baudot paper tape for transmission. At the other end, another machine converted the output paper tape back into punched cards. Later IBM machines could transmit the punched cards directly.
Self checking codes for data transmission
The same issue has other articles that may be of interest:
Stock Ticker switching
Soldering Fluxes