<s>
The	O
HP-IL	B-Architecture
(	O
Hewlett-Packard	O
Interface	O
Loop	O
)	O
,	O
was	O
a	O
short-range	O
interconnection	O
bus	O
or	O
network	O
introduced	O
by	O
Hewlett-Packard	O
in	O
the	O
early	O
1980s	O
.	O
</s>
<s>
It	O
enabled	O
many	O
devices	O
such	O
as	O
printers	O
,	O
plotters	O
,	O
displays	O
,	O
storage	O
devices	O
(	O
floppy	B-Device
disk	I-Device
drives	I-Device
and	O
tape	O
drives	O
)	O
,	O
test	O
equipment	O
,	O
etc	O
.	O
</s>
<s>
to	O
be	O
connected	O
to	O
programmable	O
calculators	O
such	O
as	O
the	O
HP-41C	B-Device
,	O
HP-71B	B-Device
and	O
HP-75C/D	B-Device
,	O
the	O
80-series	B-Device
and	O
HP-110	B-Device
computers	O
,	O
as	O
well	O
as	O
generic	O
ISA	B-Architecture
bus	I-Architecture
based	O
PCs	B-Device
.	O
</s>
<s>
As	O
its	O
name	O
implies	O
,	O
an	O
HP-IL	B-Architecture
network	O
formed	O
a	O
loop	O
(	O
i.e.	O
</s>
<s>
it	O
was	O
a	O
Ring	B-Architecture
network	I-Architecture
)	O
:	O
each	O
device	O
in	O
the	O
loop	O
had	O
a	O
pair	O
of	O
two-wire	O
connections	O
,	O
one	O
designated	O
in	O
,	O
which	O
received	O
messages	O
from	O
the	O
previous	O
device	O
in	O
the	O
loop	O
;	O
and	O
one	O
designated	O
out	O
,	O
which	O
delivered	O
messages	O
to	O
the	O
next	O
device	O
in	O
the	O
loop	O
.	O
</s>
<s>
HP-IL	B-Architecture
cables	O
utilize	O
a	O
unique	O
two-pin	O
connector	O
design	O
with	O
polarizing	O
"	O
D	O
"	O
-shaped	O
shells	O
,	O
and	O
can	O
be	O
connected	O
together	O
without	O
further	O
adapters	O
to	O
extend	O
their	O
length	O
.	O
</s>
<s>
HP-IL	B-Architecture
uses	O
a	O
token	B-Protocol
passing	I-Protocol
protocol	O
for	O
media	O
access	O
control	O
:	O
messages	O
are	O
passed	O
from	O
one	O
device	O
to	O
the	O
next	O
until	O
they	O
return	O
to	O
the	O
originator	O
.	O
</s>
<s>
Most	O
devices	O
that	O
were	O
designed	O
to	O
be	O
used	O
as	O
controllers	O
were	O
fixed	O
in	O
that	O
role	O
,	O
but	O
the	O
HP-71B	B-Device
was	O
capable	O
of	O
assuming	O
either	O
controller	O
or	O
device	O
mode	O
;	O
and	O
with	O
the	O
HP	O
82402	O
Dual	O
HP-IL	B-Architecture
Adapter	O
,	O
the	O
HP-71B	B-Device
could	O
even	O
be	O
configured	O
with	O
multiple	O
loops	O
.	O
</s>
<s>
Hewlett-Packard	O
developed	O
a	O
range	O
of	O
devices	O
to	O
be	O
connected	O
to	O
the	O
HP-IL	B-Architecture
,	O
mostly	O
peripherals	O
such	O
as	O
printers	O
and	O
storage	O
devices	O
for	O
calculators	O
.	O
</s>
<s>
Through	O
the	O
82169A	O
HP-IL/HP	O
-IB	O
Interface	O
,	O
HP-IL	B-Architecture
controllers	O
could	O
be	O
connected	O
to	O
instruments	O
with	O
an	O
HP-IB	O
(	O
aka	O
GPIB	O
or	O
IEEE-488	O
)	O
interface	O
,	O
or	O
vice	O
versa	O
.	O
</s>
<s>
There	O
were	O
also	O
plans	O
to	O
make	O
test	O
equipment	O
with	O
IL	O
interfaces	O
,	O
but	O
apart	O
from	O
the	O
somewhat	O
popular	O
3468A	O
multimeter	O
,	O
only	O
a	O
few	O
devices	O
were	O
introduced	O
before	O
HP-IL	B-Architecture
itself	O
became	O
obsolete	O
.	O
</s>
<s>
Several	O
HP	O
calculators	O
were	O
offered	O
with	O
HP-IL	B-Architecture
interfaces	O
.	O
</s>
<s>
In	O
the	O
HP-75C/D	B-Device
it	O
was	O
built	O
in	O
,	O
in	O
others	O
such	O
as	O
the	O
HP-71	O
and	O
HP-41	B-Device
,	O
plug	O
in	O
interface	O
modules	O
were	O
available	O
(	O
such	O
as	O
the	O
HP82160A	O
for	O
the	O
HP-41	B-Device
)	O
.	O
</s>
<s>
Popular	O
uses	O
for	O
the	O
HP-IL	B-Architecture
on	O
the	O
calculators	O
included	O
printing	O
(	O
using	O
the	O
HP	O
82162A	O
thermal	O
printer	O
)	O
and	O
cassette	O
file	O
storage	O
(	O
through	O
the	O
HP	O
82161A	O
digital	O
cassette	O
drive	O
)	O
.	O
</s>
<s>
Translator	O
mode	O
is	O
adequate	O
for	O
systems	O
where	O
only	O
one	O
controller	O
is	O
present	O
(	O
typically	O
a	O
calculator	O
on	O
HP-IL	B-Architecture
)	O
,	O
while	O
Mailbox	O
mode	O
applies	O
when	O
there	O
are	O
separate	O
controllers	O
present	O
on	O
both	O
buses	O
.	O
</s>
<s>
In	O
Translator	O
mode	O
with	O
an	O
HP-IL	B-Architecture
controller	O
,	O
the	O
default	O
addressing	O
mode	O
is	O
to	O
connect	O
the	O
converter	O
as	O
the	O
last	O
device	O
in	O
the	O
HP-IL	B-Architecture
loop	O
,	O
to	O
set	O
its	O
own	O
HP-IB	O
address	O
higher	O
than	O
the	O
number	O
of	O
devices	O
on	O
the	O
HP-IL	B-Architecture
loop	O
,	O
and	O
to	O
set	O
the	O
addresses	O
of	O
devices	O
to	O
be	O
addressed	O
on	O
the	O
HP-IB	O
side	O
must	O
be	O
higher	O
than	O
the	O
converter	O
's	O
address	O
.	O
</s>
<s>
HP	O
5890	O
Gas	O
Chromatograph	O
and	O
companion	O
Autosampler	O
HP	O
7673	O
have	O
an	O
HP-IL	B-Architecture
interface	O
option	O
for	O
instrument	O
programming	O
and	O
data	O
logging	O
using	O
the	O
HP	O
19405A	O
Sampler/Event	O
Control	O
Module	O
(	O
S/ECM	O
)	O
and	O
the	O
HP	O
3392A	O
Gas	O
Chromatograph	O
Integrator	O
as	O
controller	O
.	O
</s>
