<s>
In	O
data	O
communications	O
,	O
an	O
automatic	B-Device
switching	I-Device
system	I-Device
is	O
a	O
switching	B-Device
system	I-Device
in	O
which	O
all	O
the	O
operations	O
required	O
to	O
execute	O
the	O
three	O
phases	O
of	O
Information	O
transfer	O
transactions	O
are	O
automatically	O
executed	O
in	O
response	O
to	O
signals	O
from	O
a	O
user	O
end-instrument	O
.	O
</s>
<s>
In	O
an	O
automatic	B-Device
switching	I-Device
system	I-Device
,	O
the	O
information-transfer	O
transaction	O
is	O
performed	O
without	O
human	O
intervention	O
,	O
except	O
for	O
initiation	O
of	O
the	O
access	O
phase	O
and	O
the	O
disengagement	O
phase	O
by	O
a	O
user	O
.	O
</s>
<s>
This	O
distinction	O
lost	O
importance	O
as	O
manual	B-Device
switching	I-Device
declined	O
during	O
the	O
20th	O
century	O
.	O
</s>
