<s>
XID	B-Algorithm
or	O
Transducer	O
ID™	O
is	O
a	O
device	O
communications	O
bus	B-General_Concept
system	I-General_Concept
designed	O
by	O
Airmar	O
Technology	O
Corp.	O
,	O
US	O
to	O
enable	O
an	O
echosounder	O
to	O
identify	O
the	O
type	O
of	O
ultrasonic	B-Algorithm
transducer	I-Algorithm
being	O
connected	O
.	O
</s>
<s>
This	O
allows	O
the	O
echosounder	O
to	O
adjust	O
for	O
the	O
specific	O
properties	O
of	O
the	O
transducer	B-Algorithm
such	O
as	O
frequency	O
,	O
power	O
rating	O
,	O
beam	O
pattern	O
.	O
</s>
<s>
Communication	O
is	O
done	O
over	O
a	O
single	O
wire	O
in	O
a	O
controller-device	O
pattern	O
with	O
the	O
echosounder	O
as	O
controller	O
,	O
and	O
the	O
transducer	B-Algorithm
as	O
device	O
.	O
</s>
<s>
"	O
reset	O
"	O
aborts	O
all	O
commands	O
and	O
instructs	O
transducer	B-Algorithm
to	O
enter	O
its	O
initial	O
state	O
.	O
</s>
<s>
The	O
transducer	B-Algorithm
's	O
controller	O
is	O
attached	O
to	O
the	O
signalling	O
line	O
via	O
a	O
bidirectional	O
IO	O
pin	O
with	O
a	O
weak	O
pull-up	O
resistor	O
.	O
</s>
<s>
If	O
the	O
transducer	B-Algorithm
's	O
processor	O
is	O
not	O
able	O
to	O
respond	O
,	O
the	O
bus	O
will	O
remain	O
high	O
during	O
the	O
read	O
.	O
</s>
<s>
If	O
the	O
transducer	B-Algorithm
's	O
processor	O
is	O
waiting	O
for	O
a	O
command	O
,	O
it	O
answers	O
the	O
"	O
read	O
"	O
bit	O
primitive	O
command	O
by	O
pulling	O
the	O
bus	O
to	O
low	O
.	O
</s>
