[Coco] tape format

[John Guin]

Hi Roger,

For some reason, I thought the Coco did have 1500 Hz cassette system.  I
seem to remember it being exactly 5 times faster than the Commodore.

In any event, what was the speed of the Coco cassette?

John

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of Roger Taylor
Sent: Monday, November 17, 2008 4:45 PM
To: cocolist for Color Computer Enthusiasts
Subject: [Coco] tape format

Could the CoCo have had a more reliable tape format?

Read this page:

http://en.wikipedia.org/wiki/Kansas_City_standard

I think the CoCo could have had a more reliable format (perhaps) if a
1500hz/3000/hz system was used, or maybe even 2400hz/4800hz, either format,
but outputting 2 cycles of the faster wave.  The standard CoCo format
outputs 1 cycle of both waves, causing a wobbly format that's bot easy to
get out of sync, and easy to misread the faster cycle on cheap media.

If 2 cycles were used you'd get a more reliable load, I think.   The 
time length for a 1-bit would be the same for a 0-bit.  This could give a
faster format even before the 2mhz POKE.  I think a 4000 baud format isn't
impossible.

Back in the BBS days I experimented with using a VCR's audio line to record
2mhz cassette saves, and it worked.  What I did was save VDG screens in a
series using CSAVEM and then the loader read them back from the VCR tape
pretty fast.  This was mainly just to see how fast the loads were and if
there were no errors, etc.

The regular audio tape decks couldn't handle the 2mhz saves/loads for some
reason.  I don't know if it's the save or the load that goes wrong, but it's
not the CoCo itself.  Again, I confirmed this using digital devices such as
an MD Walkman and a recent Audio Voice Recorder ($39 at Wal-Mart).  That
thing records through Line In, saves as MP3 and has a USB cable for your PC.
Using that little device you could move CoCo cassettes to the PC, I'm sure.
Never tried.




--
Roger Taylor

http://www.wordofthedayonline.com


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