<s>
cu	B-Protocol
(	O
"	O
call	O
Unix	B-Application
"	O
)	O
is	O
a	O
Unix	B-Application
utility	O
for	O
establishing	O
a	O
connection	O
between	O
two	O
computer	O
systems	O
via	O
a	O
serial	B-Protocol
port	I-Protocol
to	O
another	O
computer	O
system	O
.	O
</s>
<s>
When	O
cu	B-Protocol
was	O
originally	O
created	O
,	O
connections	O
to	O
remote	O
systems	O
were	O
most	O
often	O
done	O
by	O
phone	O
,	O
and	O
cu	B-Protocol
was	O
used	O
in	O
conjunction	O
with	O
UUCP	B-Protocol
utilities	O
to	O
transfer	O
data	O
via	O
a	O
modem	B-Application
.	O
</s>
<s>
Now	O
that	O
intersystem	O
communications	O
are	O
much	O
more	O
easily	O
and	O
reliably	O
handled	O
via	O
Internet	O
connections	O
,	O
its	O
more	O
typical	O
use	O
is	O
to	O
establish	O
a	O
terminal	B-Application
connection	O
to	O
another	O
system	O
via	O
a	O
modem	B-Application
or	O
direct	O
cabling	O
.	O
</s>
<s>
It	O
was	O
originally	O
released	O
as	O
part	O
of	O
the	O
4.2BSD	O
Unix	B-Application
operating	I-Application
system	I-Application
in	O
1983	O
,	O
and	O
is	O
included	O
in	O
many	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
including	O
Solaris	B-Application
and	O
Linux	B-Application
.	O
</s>
