This discussion with attached source code and patent documents might help answer your question in detail:
https://www.vcfed.org/forum/forum/genres/tandy-radio-shack/57410-story-behind-1500-baud-decisions Jerry On Tue, May 25, 2021, 9:42 PM Douglas Quagliana <[email protected]> wrote: > The official specs that I found for the cassette port say that it runs at > 1500 bps, but the bits are sent as a single 1200 Hz cycle or a single 2400 > Hz cycle so the length of a single bit varies depending on whether it is a > one or a zero. > > If you assumed an average density of ones and zeroes then the bit rate > would be the average or 1800bps, and if you said the user only "gets" eight > bits for every nine saved to tape then you would have 8/9th of 1800bps > which would be 1600, hmmm... that doesnt work out to 1500 either. > > So, how do you get 1500bps as the cassette data rate specification? > > Douglas > > > > >
