4 Dec
2000
4 Dec
'00
6:05 p.m.
A tad over two years ago, there was some dialogue about the Kansas City
standard for cassette recording of microcomputer files, and a chap named
Heinz W. Wiggeshoff provided some information via
alt.folklore.computers, and offered both images of programatic nature and
circuit information on request. (See following.)
If anyone obtained those images and circuit information, please respond
to philpem(a)btinternet.com with Cc to me.
Many thanks.
- don
=================================
From
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Tue Dec 9 12:52:46 1997
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From: ab528(a)FreeNet.Carleton.CA (Heinz W. Wiggeshoff)
Newsgroups: alt.folklore.computers
Subject: Re: Kansas City cassette recording format
Date: 9 Dec 1997 19:00:30 GMT
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Stephen Crane (jsc(a)outoften.doc.ic.ac.uk) writes:
Anyone out there got any technical information about
this? I have
some cassettes of varying age and quality whose information I'd like
to retrieve, preferably using my PC's audio card. Ideally, someone
will have written a program for Linux which does this but, given the
info, I'll have a bash at it over Xmas.
From Microprocessor Interfacing Techniques by
Austin Lesea and Rodnay Zaks (whatever happened to him?)
c/r 1978 SYBEX Inc.
ISBN 0-89588-003-2
p. 128
KANSAS CITY STANDARD
In order to use these inexpensive recorders in the hobby market,
a standard was proposed and adopted by hobbyists. Using frequency
shift keying techniques, and frequency double frequency [sic] modem
techniques, this standard is easy to use. The drawback is the data
rate of 30 characters per second.
The system takes standard serial RS-232C data ... and converts
each bit to either 8 cycles of 2400 hertz (a "1") or 4 cycles of
1200 hertz (a "0"). To generate this, only a few flip-flips [sic]
are required along with a quad NAND gate. Shown in Fig. 4-55 is the
modulator.
[Image sent on request]
[Circuit function, ditto]
The demodulator must detect whether 1200 hertz or 2400 hertz
tones are present. There are many ways of doing this; however a
common one is to detect zero crossings of the input signal. This
will generate either 2400 or 4800 pulses per second.
[Circuit details sent on request]
The circuit for the demodulator appears in Fig. 4-56. The de-
modulator timing appears in Fig. 4-57. Note how one gets back what
one started with, along with the necessary clock information.
If the tape speed varies, the data may still be recovered as the
clock information will insure the UART receives the proper timing
signal.
No special software is needed as this interface makes the cassette
look like a paper-tape, punch-reader combination to the computer.
[Images sent on request]
(This format is found between the KIM cassette interface, and the
One Chip Digital Cassette controller using the NEC UPD371D.)
(Surprisingly, the documentation for my Heathkit ETA-3400 only
mentions the frequencies, not the details of the encoding.)
9 Dec
9 Dec
11:12 p.m.
On Mon, 4 Dec 2000, Don Maslin wrote:
A tad over two years ago, there was some dialogue
about the Kansas City
standard for cassette recording of microcomputer files, and a chap named
Heinz W. Wiggeshoff provided some information via
alt.folklore.computers, and offered both images of programatic nature and
circuit information on request. (See following.)
If anyone obtained those images and circuit information, please respond
to philpem(a)btinternet.com with Cc to me.
<...>
From Microprocessor Interfacing Techniques by
Austin Lesea and Rodnay Zaks (whatever happened to him?)
c/r 1978 SYBEX Inc.
ISBN 0-89588-003-2
p. 128
I just found my copy of this. Does someone still need something scanned?
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
10 Dec
10 Dec
12:36 a.m.
On Sat, 9 Dec 2000, Sellam Ismail wrote:
On Mon, 4 Dec 2000, Don Maslin wrote:
I think that what 'philpem' was looking for was not the stuff from Lesea
and Zaks, but the circuit information and software images that
Wiggeshoff offered to send on request.
- don
A tad over two years ago, there was some dialogue
about the Kansas City
standard for cassette recording of microcomputer files, and a chap named
Heinz W. Wiggeshoff provided some information via
alt.folklore.computers, and offered both images of programatic nature and
circuit information on request. (See following.)
If anyone obtained those images and circuit information, please respond
to philpem(a)btinternet.com with Cc to me.
<...>
From Microprocessor Interfacing Techniques by
Austin Lesea and Rodnay Zaks (whatever happened to him?)
c/r 1978 SYBEX Inc.
ISBN 0-89588-003-2
p. 128
I just found my copy of this. Does someone still need something scanned? Sellam Ismail
Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
11:36 a.m.
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11:56 a.m.
Tony Duell wrote:
I have a scanner and would like to build one.
--
Linux Home Automation Neil Cherry ncherry(a)home.net
http://members.home.net/ncherry (Text only)
http://meltingpot.fortunecity.com/lightsey/52 (Graphics)
http://linuxha.sourceforge.net/ (SourceForge)
I think that what 'philpem' was looking
for was not the stuff from Lesea
and Zaks, but the circuit information and software images that
Wiggeshoff offered to send on request.
A number of years ago (heck, the prototype probably comes under the 10
year rule :-)) I designed a little interface to convert between audio
cassette data (using the standard 1200Hz/2400Hz tones) and an RS232 port.
I know I used it to read BBC micro cassettes and BASICODE recordings into
a machine with an RS232 port. It works at up to 1200 baud. The Tx used a
crystal clock and a set of counters, the Rx used the classic 2 monostable
circuit. And I even used one of the handshake lines to turn a relay on
and off to control the cassette motor.
I can't find the physical unit, but I can find the schematics and parts
list for it. I'd be happy to make one or 2 copies of this (but not many
more) and to send them out. I'd also have no objections to further
distribution, so if somebody wants to scan them and stick them on a
suitable website, that would be fine.
If anyone is interested, let me know.
12:45 p.m.
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11 Dec
11 Dec
8:24 a.m.
On Sat, 9 Dec 2000 21:12:49 -0800 (PST) Sellam Ismail
<foo(a)siconic.com> wrote:
^^^^^^^^^^^
Rodnay Zaks, the guru of "Programming the 6502", amongst
others. I still have the copy that I bought in about 1981,
as well as the "6502 Applications Book" and some of the
later ones like the CP/M guide and the Wordstar guide. I
think these were Sybex books but not written by Rodnay Zaks.
Sybex is still around, publishing a range of books with
chimpanzees on the covers. So, whatever did happen to Mr.
Zaks?
I think I have a copy, too. I'll have a look for it. Also
seem to recall circuits published for Kansas City tape
decoders in electronics magazines. Byte, even, when it was
a more hardware-oriented magazine.
--
John Honniball
Email: John.Honniball(a)uwe.ac.uk
University of the West of England
On Mon, 4 Dec 2000, Don Maslin wrote:
...
If anyone
obtained those images and circuit information, please respond
to philpem(a)btinternet.com with Cc to me.
<...>
>
> From Microprocessor Interfacing Techniques by
> Austin Lesea and Rodnay Zaks (whatever happened to him?) c/r 1978
SYBEX Inc.
ISBN 0-89588-003-2
p. 128
I just found my copy of this. Does someone still need something scanned?
11:02 a.m.
On Mon, 11 Dec 2000, John Honniball wrote:
Rodnay Zaks, the guru of "Programming the
6502", amongst
others. I still have the copy that I bought in about 1981,
as well as the "6502 Applications Book" and some of the
later ones like the CP/M guide and the Wordstar guide. I
think these were Sybex books but not written by Rodnay Zaks.
My copy is indeed published by Sybex.
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
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days inactive
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7 comments
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-
ard＠p850ug1.demon.co.uk -
donm＠cts.com -
foo＠siconic.com -
John.Honniball＠uwe.ac.uk -
ncherry＠home.net