Computer Audio Tape Formats - test-drb@ccmp.vtda.org

17 Dec 2002

On Dec 17, 13:50, tim lindner wrote:
...
  I am looking for information regarding how various
computers wrote
 information to audio tapes. 
...
  I am contemplating creating an audio tape anaylzer to
help me recover
 some data. I would like to make the program useful to thoes outside the
 Color Computer community. But first I need to understand all of the
 different methods used to put data on audio tape. 
Look up "Kansas City" and "CUTS" on the web...  many machines used
some
derivative.

For 300 baud:
logic 0 is 4 cycles of a 1.2kHz tone
logic 1 is 8 cycles of a 2.4kHz tone
lead-in is 2.4kHz, followed by a zero byte

Similarly for 1200 baud but fewer cycles.

CUTS (Computer Users Tape Interface) was derived from KC format, which was
so called because it came out of a meeting held in Kansas City in 1975.
 It's backwards compatible.

Also look up Don Tarbell's system.  I can't remember what the tones were,
but it's about 600 baud, IIRC.

None of this tells you about the format of the data, of course -- block
headers (if any), checksums/CRCs, etc.  That tended to vary.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York