I learned to program in high school on a Teletype Model 33 ASR that dialed into to a timesharing service. This was the version with a paper tape punch and reade

I learned to program in high school on a Teletype Model 33 ASR that dialed into to a timesharing service. This was the version with a paper tape punch and reader. Dial-up time was very expensive, somewhere around $50/hour in today's dollars. So we would punch our code onto a paper tape, then print it out locally to review it, and finally dial in, run the paper tape through and wait for the printout from our program, and immediately disconnect. In theory, CR LF should have been enough at the end of a line, but we found that sometimes, especially after a long line, the next line would start printing before the paper had fully advanced. To play it safe, we would punch CR LF RUBOUT. RUBOUT was a character with all eight holes punched in the tape, i.e. 0xFF. By convention, this code was ignored by any system that received it. The intended use of RUBOUT was to correct an error you made when punching a tape. You would back up the tape as many characters as you got wrong, then punch that many RUBOUTs, and continue from there. Because RUBOUT had every hole punched out, it would erase any error. And it also served to give the paper a little more time to advance when we punched CR LF RUBOUT. Maybe our machine was in need of some oiling or adjustment. The Model 33 was designed as a light-duty machine, unlike the more rugged Models 28 and 35.