<s>
ccTalk	B-Protocol
(	O
pronounced	O
see-see-talk	O
)	O
is	O
a	O
serial	B-Protocol
protocol	O
in	O
widespread	O
use	O
throughout	O
the	O
money	O
transaction	O
and	O
point-of-sale	O
industry	O
.	O
</s>
<s>
Peripherals	B-Device
such	O
as	O
the	O
currency	O
detectors	O
for	O
coins	O
and	O
banknotes	O
found	O
in	O
a	O
diverse	O
range	O
of	O
automatic	O
payment	O
equipment	O
such	O
as	O
transportation	O
,	O
ticketing	O
,	O
payphones	O
,	O
amusement	O
machines	O
,	O
and	O
retail	O
cash	O
management	O
use	O
ccTalk	B-Protocol
to	O
talk	O
to	O
the	O
host	O
controller	O
.	O
</s>
<s>
The	O
ccTalk	B-Protocol
protocol	O
is	O
one	O
of	O
2	O
protocols	O
specified	O
by	O
BACTA	O
for	O
use	O
in	O
all	O
AWP	O
machines	O
with	O
serial	B-Protocol
coin	O
acceptors	O
.	O
</s>
<s>
The	O
ccTalk	B-Protocol
protocol	O
is	O
an	O
open	O
standard	O
.	O
</s>
<s>
It	O
operates	O
at	O
TTL	O
voltages	O
and	O
is	O
‘	O
multi-drop	B-Architecture
’	O
i.e.	O
</s>
<s>
peripherals	B-Device
can	O
be	O
connected	O
to	O
a	O
common	O
bus	O
and	O
are	O
logically	O
separated	O
by	O
a	O
device	O
address	O
.	O
</s>
<s>
Each	O
peripheral	O
on	O
the	O
ccTalk	B-Protocol
bus	O
must	O
have	O
a	O
unique	O
address	O
.	O
</s>
<s>
Low	O
cost	O
bridge	O
chips	O
are	O
now	O
available	O
from	O
a	O
number	O
of	O
manufacturers	O
to	O
allow	O
ccTalk	B-Protocol
to	O
run	O
over	O
USB	O
at	O
baud	O
rates	O
of	O
at	O
least	O
1	O
Mbit/s	O
.	O
</s>
<s>
ccTalk	B-Protocol
protocol	O
stacks	O
have	O
been	O
implemented	O
on	O
a	O
range	O
of	O
devices	O
from	O
tiny	O
Microchip	O
microcontrollers	B-Architecture
with	O
512	O
bytes	B-Application
of	O
ROM	B-Device
to	O
powerful	O
ARM7	O
32-bit	O
processors	O
.	O
</s>
<s>
The	O
protocol	O
supports	O
all	O
standard	O
operations	O
for	O
electronic	O
devices	O
such	O
as	O
flash	B-Device
upgrading	O
of	O
firmware	O
,	O
secure	O
transfer	O
of	O
data	O
and	O
detailed	O
diagnostic	O
information	O
.	O
</s>
<s>
Advantages	O
of	O
ccTalk	B-Protocol
include	O
low	O
cost	O
UART	O
technology	O
,	O
a	O
simple-to-understand	O
packet	O
structure	O
,	O
an	O
easily	O
expandable	O
command	O
interface	O
and	O
no	O
licensing	O
requirements	O
.	O
</s>
<s>
In	O
2010	O
,	O
DES	B-Algorithm
encryption	O
was	O
added	O
to	O
certain	O
commands	O
so	O
that	O
it	O
could	O
be	O
made	O
more	O
resilient	O
against	O
attacks	O
on	O
the	O
bus	O
.	O
</s>
<s>
Each	O
peripheral	O
has	O
its	O
own	O
unique	O
DES	B-Algorithm
key	O
.	O
</s>
<s>
The	O
ccTalk	B-Protocol
protocol	O
is	O
a	O
byte-oriented	O
protocol	O
.	O
</s>
<s>
The	O
series	O
of	O
bytes	B-Application
in	O
a	O
message	O
--	O
represented	O
above	O
as	O
a	O
series	O
of	O
decimal	O
numbers	O
--	O
is	O
transmitted	O
as	O
8-N-1	O
.	O
</s>
<s>
Many	O
devices	O
have	O
single	O
electrical	O
connector	O
that	O
carries	O
both	O
power	O
(	O
typically	O
+12	O
V	O
or	O
+24	O
V	O
)	O
and	O
the	O
ccTalk	B-Protocol
data	O
over	O
a	O
total	O
of	O
4	O
wires	O
.	O
</s>
<s>
To	O
reduce	O
cost	O
,	O
for	O
short	O
interconnection	O
distances	O
CPI	O
recommends	O
sending	O
ccTalk	B-Protocol
data	O
over	O
an	O
unbalanced	O
multi-drop	B-Architecture
open-collector	O
interface	O
:	O
both	O
transmit	O
and	O
receive	O
messages	O
occur	O
on	O
the	O
same	O
bi-directional	O
serial	B-Protocol
DATA	O
line	O
at	O
TTL	O
level	O
,	O
driven	O
through	O
an	O
open-collector	O
NPN	O
transistor	O
.	O
</s>
<s>
For	O
longer	O
distances	O
,	O
CPI	O
recommends	O
sending	O
ccTalk	B-Protocol
data	O
over	O
a	O
balanced	O
multi-drop	B-Architecture
RS-485	O
driver	O
interface	O
,	O
also	O
nominally	O
+5	O
V	O
and	O
0	O
V	O
.	O
</s>
<s>
Secure	O
peripherals	B-Device
require	O
all	O
bytes	B-Application
of	O
a	O
message	O
to	O
be	O
encrypted	O
,	O
except	O
for	O
the	O
first	O
two	O
bytes	B-Application
--	O
the	O
destination	O
address	O
byte	B-Application
and	O
the	O
data-length	O
byte	B-Application
are	O
never	O
encrypted	O
to	O
allow	O
standard	O
and	O
secure	O
peripherals	B-Device
to	O
be	O
mixed	O
on	O
the	O
same	O
bus	O
.	O
</s>
<s>
The	O
total	O
length	O
of	O
a	O
message	O
packet	O
can	O
range	O
from	O
a	O
minimum	O
of	O
5	O
bytes	B-Application
(	O
data-length	O
byte	B-Application
equal	O
to	O
0	O
)	O
to	O
260	O
bytes	B-Application
(	O
data-length	O
byte	B-Application
equal	O
to	O
255	O
)	O
.	O
</s>
<s>
A	O
number	O
of	O
associated	O
standards	O
have	O
emerged	O
over	O
the	O
years	O
from	O
within	O
the	O
ccTalk	B-Protocol
specification	O
.	O
</s>
