<s>
The	O
Texas	O
Instruments	O
TI-74	B-Device
Basicalc	O
is	O
a	O
type	O
of	O
programmable	O
calculator	B-Application
,	O
which	O
was	O
released	O
in	O
1985	O
to	O
replace	O
the	O
Compact	B-Device
Computer	I-Device
40	I-Device
.	O
</s>
<s>
The	O
TI-74	B-Device
'	O
s	O
architecture	O
is	O
descended	O
from	O
the	O
never-released	O
TI	B-Device
CC-40	I-Device
Plus	O
.	O
</s>
<s>
TI	O
utilized	O
the	O
CC-40	B-Device
Plus	O
ROM	O
to	O
create	O
the	O
TI-74	B-Device
'	O
s	O
BIOS	O
;	O
it	O
removed	O
the	O
CC-40	B-Device
'	O
s	O
internal	O
debugger	O
to	O
gain	O
enough	O
space	O
to	O
add	O
calculator	B-Application
mode	O
to	O
the	O
TI-74	B-Device
.	O
</s>
<s>
The	O
CC-40	B-Device
Plus	O
 '	O
cassette	O
routines	O
were	O
reused	O
in	O
the	O
TI-74	B-Device
,	O
and	O
the	O
CC-40	B-Device
'	O
s	O
Hexbus	O
port	O
underwent	O
a	O
physical	O
footprint	O
change	O
and	O
was	O
renamed	O
to	O
Dockbus	O
.	O
</s>
<s>
The	O
Hexbus	O
protocol	O
is	O
100%	O
compatible	O
between	O
the	O
CC-40	B-Device
and	O
TI-74	B-Device
with	O
an	O
adapter	O
.	O
</s>
<s>
One	O
variant	O
,	O
the	O
TI-74S	B-Device
,	O
has	O
a	O
blank	O
faceplate	O
instead	O
of	O
secondary	O
functions	O
to	O
allow	O
for	O
customization	O
(	O
otherwise	O
it	O
is	O
the	O
same	O
as	O
the	O
74	O
)	O
.	O
</s>
<s>
The	O
TI-95	B-Device
,	O
released	O
at	O
the	O
same	O
time	O
,	O
was	O
a	O
keystroke	O
programmable	O
descendant	O
of	O
the	O
TI-59	B-Device
and	O
TI-66	O
,	O
with	O
the	O
same	O
general	O
form	O
factor	O
,	O
but	O
a	O
two-line	O
display	O
(	O
the	O
second	O
line	O
was	O
for	O
function	O
key	O
definitions	O
)	O
.	O
</s>
