paper tape punch / reader

There are two questions here. One is physical format: placement and size of holes and width of tape. I know of 2, 5, 6, and 8 bit tape. Hole pitch is 0.1 inch, and the feed hole is small while the data holes are bigger. (I don?t know the sizes but all the ones I?ve seen are consistent.) Width is 0.2 inch + 0.1 * number of data bits. So 8 bit tape is 1 inch wide. Feed holes are between the 3rd and 4th row on 8 bit, between the 2nd and 3rd on 5 bit, between the two rows on 2 bit, and I?m not sure where on 6 bit. (In the middle, probably.) 2 bit is Wheatstone, for encoding Morse code. 5 bit is ?Baudot?, i.e., Murray code, the older telegraph system. 6 bit is for early automated typesetters (automated Linotypes or early phototypesetters). 8 bit we all know. Oh yes, there is much wider tape (19 channels???) for Monotype machines. I know nothing about those other than the brief reference I saw in the excellent book ?Travels in Computerland?. The other question is encoding. 2 channel tape is Morse (specifically International Morse, it can?t encode American Morse). 5 channel is Baudot/Murray, which actually comes in a half dozen variations that generally affect just the ?figures shift?. 6 channel also comes in a pile of variations, for example one used for stock listings which has lots of different fractions. And 8 channel can encode 7 or 8 bit codes (and probably even 6 bit codes on old computers that used that), anywhere from ASCII to the many Flexowriter codes to BCD and EBCDIC. As for the original question: a one inch tape machine from CNC equipment should be just like any other 8 bit tape as far as the physical aspects are concerned. So you should just need to worry about the electrical interfacing. paul On May 9, 2014, at 5:56 AM, Simon Claessen <simski at dds.nl> wrote: