12/11/2023 0 Comments Data punch tape creator![]() Murray added a typewriter style keyboard, mechanical code conversion and format characters (LF, CR, BELL) making the output (more) like a typed letter. All text was a continous stream, with out any control characters (beside erase that is). *3 - Baudot's original code was made to be entered using a piano like keyboard with 5 keys, with the letters arranged in a way to ease typing. *2 - Yes, the very same man who developed the bridge named after him, well known to anyone who ever peeked into electronics. Numeric interpretation only came with computers. Holes represented a sequential value, not a numeric one. While early computers used many various formats, next to everything after 1963 went for ASCII and 8 hole paper tapes for their control applications, new mini computers and later micros. Not to mention that ASCII as well finally made numeric values the base of symbols. It wasn't until the 7/8 bit ASCII TTYs, more specific the Teletype Model 33, that made a compatible 1 inch wide tape the defacto standard for everything up to 8 holes. There were in addition many codes that used constant bit numbers, like 3-out-of-7 (More, CCITT#3) or 4-out-of-7 (CCIR 476). Even with an installed 8 hole punch installed, codes used were 7 bit, using the 8th hole at maximum for parity information - or special markings. 'The' Flexowriter is often mentioned as a first, but beside that there was no single model, but a family of different and often customer specific models, it did use many different formats. In fact, some systems (like certain Friden Flexowriter punches) were intended to use arbitrary wide sheets to allow punching of data along files. To enhance this some readers were made in a way to use no left stop, not limiting the tape width at all (*5). It saved not only cost in design and production, but resulted in great compatibility with the existing 5 hole types. Manufacturer usually extended existing punch designs by adding more holes to the 'left', keeping all transport mechanic (and thus the transport holes) the same. Width of these tapes were specific to each extension. Later 6.9 hole systems imply extended that tape with more holes, following the standard, to the 'left' - and of course used way different encodings.
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