<s>
The	O
Kansas	B-Device
City	I-Device
standard	I-Device
(	O
KCS	B-Device
)	O
,	O
or	O
Byte	B-Device
standard	I-Device
,	O
is	O
a	O
data	O
storage	O
protocol	O
for	O
standard	O
cassette	B-Device
tapes	I-Device
at	O
.	O
</s>
<s>
It	O
originated	O
in	O
a	O
symposium	O
sponsored	O
by	O
Byte	B-Application
magazine	O
in	O
November	O
1975	O
in	O
Kansas	O
City	O
,	O
Missouri	O
to	O
develop	O
a	O
standard	O
for	O
the	O
storage	O
of	O
digital	O
microcomputer	B-Architecture
data	O
on	O
inexpensive	O
consumer	O
quality	O
cassettes	O
.	O
</s>
<s>
CUTS	O
is	O
the	O
default	O
encoding	O
used	O
by	O
several	O
later	O
machine	O
families	O
,	O
including	O
those	O
from	O
Acorn	O
and	O
the	O
MSX	B-Operating_System
.	O
</s>
<s>
MSX	B-Operating_System
added	O
a	O
higher	O
2400bit/s	O
mode	O
that	O
is	O
otherwise	O
similar	O
.	O
</s>
<s>
KCS	B-Device
originated	O
from	O
the	O
earliest	O
days	O
of	O
the	O
microcomputer	B-Architecture
revolution	O
,	O
among	O
other	O
prolific	O
protocols	O
.	O
</s>
<s>
Most	O
home	O
computers	O
of	O
the	O
era	O
have	O
unique	B-General_Concept
formats	I-General_Concept
that	O
are	O
incompatible	O
with	O
anything	O
.	O
</s>
<s>
Early	O
microcomputers	B-Architecture
generally	O
use	O
punched	O
tape	O
for	O
program	O
storage	O
,	O
an	O
expensive	O
option	O
.	O
</s>
<s>
Wayne	O
Green	O
,	O
who	O
had	O
just	O
started	O
Byte	B-Application
magazine	O
,	O
wanted	O
all	O
the	O
manufacturers	O
to	O
collaborate	O
on	O
a	O
single	O
cassette	O
standard	O
.	O
</s>
<s>
After	O
the	O
meeting	O
,	O
Lee	O
Felsenstein	O
(	O
of	O
Processor	O
Technology	O
)	O
and	O
Harold	O
Mauch	O
(	O
of	O
Percom	B-Device
)	O
wrote	O
the	O
standard	O
,	O
which	O
was	O
published	O
in	O
Byte	B-Application
magazine	O
's	O
first	O
issue	O
.	O
</s>
<s>
A	O
KCS	B-Device
cassette	O
interface	O
is	O
similar	O
to	O
a	O
modem	O
connected	O
to	O
a	O
serial	B-Protocol
port	I-Protocol
.	O
</s>
<s>
The	O
1s	O
and	O
0s	O
from	O
the	O
serial	B-Protocol
port	I-Protocol
are	O
converted	O
to	O
audio	O
tones	O
using	O
audio	O
frequency-shift	O
keying	O
(	O
AFSK	O
)	O
.	O
</s>
<s>
Each	O
frame	O
starts	O
with	O
one	O
"	O
0	O
"	O
start	O
bit	O
,	O
followed	O
by	O
eight	O
data	O
bits	O
(	O
least	O
significant	O
bit	O
first	O
)	O
followed	O
by	O
two	O
"	O
1	O
"	O
stop	O
bits	O
,	O
so	O
each	O
frame	O
is	O
11	O
bits	O
,	O
for	O
a	O
data	O
rate	O
of	O
bytes	B-Application
per	O
second	O
.	O
</s>
<s>
The	O
February	O
1976	O
issue	O
of	O
Byte	B-Application
has	O
a	O
report	O
on	O
the	O
symposium	O
,	O
and	O
the	O
March	O
issue	O
features	O
two	O
hardware	O
examples	O
by	O
Don	O
Lancaster	O
and	O
Harold	O
Mauch	O
.	O
</s>
<s>
Most	O
audio	B-Device
cassette	I-Device
circuits	O
support	O
higher	O
speeds	O
.	O
</s>
<s>
A	O
word	O
,	O
usually	O
one	O
byte	B-Application
(	O
8	O
bits	O
)	O
long	O
,	O
is	O
recorded	O
in	O
little	O
endian	O
order	O
,	O
which	O
is	O
least	O
significant	O
bit	O
first	O
.	O
</s>
<s>
7-bit	O
words	O
are	O
followed	O
by	O
a	O
parity	B-Error_Name
bit	I-Error_Name
.	O
</s>
<s>
They	O
provided	O
the	O
S-100	B-Architecture
bus	I-Architecture
CUTS	O
Tape	O
I/O	O
interface	O
board	O
,	O
which	O
offers	O
both	O
CUTS	O
and	O
Kansas	B-Device
City	I-Device
standard	I-Device
support	O
to	O
any	O
S-100	O
system	O
.	O
</s>
<s>
The	O
Tarbell	B-Device
Cassette	I-Device
Interface	I-Device
,	O
which	O
,	O
according	O
to	O
early	O
PC	O
retailer	O
Stan	O
Veit	O
,	O
"	O
became	O
a	O
de	O
facto	O
standard	O
for	O
S-100	B-Architecture
computers	I-Architecture
"	O
,	O
supported	O
the	O
Kansas	B-Device
City	I-Device
Standard	I-Device
in	O
addition	O
to	O
the	O
Tarbell	B-Device
"	O
native	O
"	O
mode	O
(	O
"	O
Tarbell	B-Device
standard	O
"	O
)	O
.	O
</s>
<s>
Acorn	O
Computers	O
Ltd	O
implemented	O
a	O
1200-baud	O
variation	O
of	O
CUTS	O
in	O
its	O
BBC	B-Device
Micro	I-Device
and	O
Acorn	B-Device
Electron	I-Device
microcomputers	B-Architecture
,	O
which	O
reduced	O
a	O
"	O
0	O
"	O
bit	O
to	O
one	O
cycle	O
of	O
a	O
1200Hz	O
sine	O
wave	O
and	O
a	O
"	O
1	O
"	O
bit	O
to	O
two	O
cycles	O
of	O
a	O
2400Hz	O
wave	O
.	O
</s>
<s>
Also	O
,	O
these	O
machines	O
record	O
data	O
in	O
256-byte	O
blocks	B-General_Concept
interspersed	O
with	O
gaps	O
of	O
carrier	O
tone	O
,	O
each	O
block	O
carrying	O
a	O
sequence	O
number	O
and	O
a	O
CRC	O
checksum	O
,	O
so	O
that	O
it	O
is	O
possible	O
to	O
rewind	O
the	O
tape	O
and	O
retry	O
from	O
the	O
failed	O
block	O
when	O
a	O
read	O
error	O
occurs	O
.	O
</s>
<s>
The	O
MSX	B-Operating_System
by	O
default	O
supports	O
both	O
a	O
1200	O
baud	O
variation	O
of	O
the	O
standard	O
with	O
the	O
same	O
bit	O
encoding	O
as	O
Acorn	O
's	O
,	O
and	O
a	O
2400	O
baud	O
variant	O
which	O
doubles	O
the	O
audio	O
rate	O
—	O
a	O
"	O
0	O
"	O
bit	O
is	O
one	O
cycle	O
of	O
a	O
2400Hz	O
wave	O
and	O
a	O
"	O
1	O
"	O
bit	O
is	O
two	O
cycles	O
of	O
a	O
4800Hz	O
wave	O
.	O
</s>
<s>
Unlike	O
Acorn	O
machines	O
,	O
the	O
MSX	B-Operating_System
uses	O
two	O
"	O
1	O
"	O
stop	O
bits	O
in	O
addition	O
to	O
one	O
"	O
0	O
"	O
start	O
bit	O
,	O
so	O
the	O
effective	O
rate	O
at	O
1200	O
baud	O
is	O
approximately	O
873	O
bits	O
per	O
second	O
,	O
and	O
the	O
effective	O
rate	O
at	O
2400	O
baud	O
is	O
approximately	O
1,745	O
bits	O
per	O
second	O
.	O
</s>
<s>
Published	O
in	O
1978	O
,	O
it	O
predates	O
the	O
1982	O
patent	O
for	O
the	O
similar	O
coded	B-Protocol
mark	I-Protocol
inversion	I-Protocol
proposal	O
.	O
</s>
<s>
Several	O
use	O
the	O
S-100	B-Architecture
bus	I-Architecture
.	O
</s>
<s>
Exidy	B-Architecture
Sorcerer	I-Architecture
Optional	O
S-100	O
expansion	O
bus	O
,	O
standard	O
300	O
bit/s	O
mode	O
and	O
a	O
1200	O
baud	O
variant	O
by	O
default	O
.	O
</s>
<s>
Processor	O
Technology	O
provided	O
an	O
Intel	B-General_Concept
8080	I-General_Concept
program	O
to	O
be	O
recorded	O
.	O
</s>
<s>
Daniel	O
Meyer	O
and	O
Gary	O
Kay	O
of	O
Southwest	O
Technical	O
Products	O
(	O
SWTPC	O
)	O
arranged	O
for	O
Robert	O
Uiterwyk	O
to	O
provide	O
his	O
4K	O
BASIC	O
interpreter	O
program	O
for	O
the	O
Motorola	B-Device
6800	I-Device
microprocessor	O
.	O
</s>
<s>
The	O
May	O
1977	O
issue	O
of	O
Interface	O
Age	O
contains	O
the	O
first	O
"	O
Floppy	O
ROM	O
"	O
,	O
a	O
33	O
RPM	O
record	O
containing	O
about	O
six	O
minutes	O
of	O
Kansas	B-Device
City	I-Device
standard	I-Device
audio	O
.	O
</s>
