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Interface
Live ware
LPI
Parallel Interface
Parity
GL-2
The
connection
between two pieces
of
equipment
-
that
is,
between
a computer
and
a printer. The two basic types
of
interfaces
are
parallel
and
serial. The
word is
loosely used
to
mean
either
the
method
of connection or
the
actual
hardware used to
connect equipment,
including the circuits that control
com
-
munication. As
a
verb, it usually
means
the
act of
making the
connection.
You
,
the user: generally
acknowledged
to be
the
most
important component of
any computer system.
Lines Per Inch
:
A
measure
of line spac-
ing.
When
the
line
spacing is 6
LPI
,
the
distance between the bottom of one line
of
print and
the
bottom of the
next
is
1
/6
".
An interface in which
the
8
bits that
make
up each byte of data are
trans-
mitted simultaneously over 8 separate
wires.
A
method
of checking for errors
in
data
transmission used
in
some serial inter-
faces. The computer adds a bit
-
called
the
"
parity bit
"
-
to each byte of
data
so that the total number of 1
'sis
either
al ways even
("even parity
")
or al
ways
odd
("odd parity
").
The
printer
checks
each
inco
ming
byte plus
pari
ty
bit to
make sure the parity is co
rrect; if
it
is
n
't,
that
indicates
that the
data hasn
't been
sent
(o
r
received}
properly
,
and the
printer
signals that
a "parity error"
has
been detected.
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