17 Dec
2002
17 Dec
'02
7:54 a.m.
I am looking for information regarding how various computers wrote
information to audio tapes.
For example, the Tandy Color Computer wrote ones and zeros to audio tape
in the following format:
'one bit': one sinusoidal cycle @ 2400 Hertz.
'zero bit': one sinusoidal cycle @ 1200 Hertz.
The bit rate is variable on a CoCo tape. But averages to about 1500 bits
per second.
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.
--
tim lindner tlindner(a)ix.netcom.com
17 Dec
17 Dec
8:23 a.m.
I vaguely remember an old standard format for this kind of thing called Kansas
City (for some reason... perhaps someone else can enlighten!). A swift
google search turned up http://www.alphalink.com.au/~edsa/ which has a
utility which decodes this apparently. No connection to the site and haven't
tried it myself I must admit.
Cheers
Oliver
On Tuesday 17 December 2002 9:50 pm, tim lindner wrote:
I am looking for information regarding how various
computers wrote
information to audio tapes.
For example, the Tandy Color Computer wrote ones and zeros to audio tape
in the following format:
'one bit': one sinusoidal cycle @ 2400 Hertz.
'zero bit': one sinusoidal cycle @ 1200 Hertz.
The bit rate is variable on a CoCo tape. But averages to about 1500 bits
per second.
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.
8:44 a.m.
Tim,
I believe that many different computers used the same or very similar
method to record data to cassette.
I'm pretty sure that the Atari 8-bit and the Commodore VIC-20/C-64 tape
recorders used the same method (FSK).
Weren't the same frequencies used for FSK/Teletype ? The Commodore
"Datasette" used 300 baud as the rate (I'm pretty sure).
The Atari cassette recorders put a pause between data packets - it was very
noticeable when you listened to the audio. I don't remember the Commodore
format putting in the long delay.
Just some food for thought....
- Matt
At 01:50 PM 12/17/2002 -0800, you wrote:
I am looking for information regarding how various
computers wrote
information to audio tapes.
For example, the Tandy Color Computer wrote ones and zeros to audio tape
in the following format:
'one bit': one sinusoidal cycle @ 2400 Hertz.
'zero bit': one sinusoidal cycle @ 1200 Hertz.
The bit rate is variable on a CoCo tape. But averages to about 1500 bits
per second.
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.
--
tim lindner tlindner(a)ix.netcom.com
Matthew Sell
Programmer
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(281) 296-6066
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