<s>
A	O
wire	B-Algorithm
spring	I-Algorithm
relay	I-Algorithm
is	O
a	O
type	O
of	O
relay	O
,	O
that	O
has	O
springs	O
made	O
from	O
drawn	O
wires	O
of	O
nickel	O
silver	O
,	O
rather	O
than	O
cut	O
from	O
flat	O
sheet	O
metal	O
as	O
in	O
the	O
flat-spring	O
relay	O
.	O
</s>
<s>
Wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
entered	O
mass	O
production	O
in	O
the	O
early	O
1950s	O
.	O
</s>
<s>
Wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
were	O
the	O
most	O
suitable	O
relays	O
for	O
logic	O
and	O
computing	O
functions	O
.	O
</s>
<s>
They	O
were	O
used	O
extensively	O
in	O
markers	B-Device
,	O
which	O
were	O
special	O
purpose	O
computers	O
used	O
to	O
route	O
calls	O
in	O
crossbar	O
switch	O
central	O
offices	O
.	O
</s>
<s>
Wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
were	O
primarily	O
manufactured	O
by	O
the	O
Western	O
Electric	O
Company	O
for	O
use	O
in	O
electromechanical	O
telephone	O
exchanges	O
in	O
the	O
Bell	O
System	O
.	O
</s>
<s>
Manufacturing	O
of	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
greatly	O
declined	O
in	O
the	O
late	O
20th	O
century	O
due	O
to	O
the	O
introduction	O
of	O
digital	O
electronic	B-Device
switching	I-Device
systems	I-Device
that	O
used	O
them	O
in	O
very	O
small	O
numbers	O
.	O
</s>
<s>
A	O
wire	B-Algorithm
spring	I-Algorithm
relay	I-Algorithm
typically	O
has	O
many	O
individual	O
contacts	O
.	O
</s>
<s>
The	O
majority	O
of	O
the	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
manufactured	O
in	O
the	O
1960s	O
had	O
twelve	O
fixed	O
contacts	O
.	O
</s>
<s>
For	O
the	O
stored	B-Device
program	I-Device
control	I-Device
exchanges	I-Device
of	O
the	O
early	O
1970s	O
,	O
many	O
relays	O
were	O
made	O
with	O
steel	O
cores	O
that	O
remained	O
magnetized	O
after	O
current	O
ceased	O
to	O
flow	O
in	O
the	O
winding	O
.	O
</s>
<s>
This	O
magnetic	O
latching	O
feature	O
,	O
different	O
from	O
the	O
use	O
of	O
slugs	O
to	O
delay	O
relay	O
operation	O
,	O
was	O
used	O
in	O
the	O
arrays	O
of	O
reed	B-Algorithm
relays	I-Algorithm
that	O
switched	O
connection	O
paths	O
in	O
the	O
early	O
models	O
of	O
electronic	B-Device
switching	I-Device
systems	I-Device
.	O
</s>
<s>
A	O
miniature	O
wire	B-Algorithm
spring	I-Algorithm
relay	I-Algorithm
was	O
also	O
produced	O
,	O
starting	O
in	O
approximately	O
1974	O
as	O
part	O
of	O
the	O
1A	O
redesign	O
of	O
the	O
1ESS	B-Device
switch	I-Device
.	O
</s>
<s>
Wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
could	O
be	O
interconnected	O
to	O
create	O
the	O
typical	O
combinational	O
circuits	O
that	O
were	O
later	O
used	O
in	O
silicon	O
design	O
.	O
</s>
<s>
Memory	O
circuits	O
in	O
the	O
form	O
of	O
latches	B-General_Concept
can	O
also	O
be	O
created	O
by	O
having	O
a	O
relay	O
contact	O
complete	O
the	O
circuit	O
of	O
its	O
own	O
coil	O
when	O
operated	O
.	O
</s>
<s>
The	O
relay	O
will	O
then	O
latch	B-General_Concept
and	O
store	O
the	O
state	O
to	O
which	O
it	O
was	O
driven	O
.	O
</s>
<s>
Starting	O
in	O
the	O
1950s	O
,	O
these	O
designs	O
were	O
converted	O
to	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
,	O
making	O
them	O
faster	O
and	O
more	O
reliable	O
.	O
</s>
<s>
The	O
majority	O
of	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
were	O
used	O
in	O
5XB	B-Device
switches	I-Device
.	O
</s>
<s>
Most	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
have	O
a	O
permalloy	O
core	O
,	O
and	O
require	O
continuous	O
power	O
to	O
maintain	O
state	O
.	O
</s>
<s>
Some	O
have	O
a	O
steel	O
core	O
,	O
making	O
them	O
magnetically	O
latching	O
relays	O
,	O
similar	O
to	O
the	O
ferreed	O
and	O
remreed	O
types	O
of	O
reed	B-Algorithm
relay	I-Algorithm
.	O
</s>
<s>
Reed	B-Algorithm
relays	I-Algorithm
are	O
smaller	O
and	O
cheaper	O
,	O
thus	O
better	O
suited	O
to	O
data	O
storage	O
.	O
</s>
<s>
They	O
were	O
used	O
in	O
conjunction	O
with	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
,	O
for	O
example	O
to	O
store	O
digits	O
for	O
sending	O
to	O
other	O
crossbar	O
switching	O
offices	O
.	O
</s>
<s>
In	O
a	O
multi-frequency	O
sender	O
(	O
the	O
part	O
of	O
a	O
switch	O
which	O
sends	O
routing	O
information	O
about	O
outgoing	O
calls	O
over	O
trunk	O
lines	O
)	O
,	O
for	O
example	O
,	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
direct	O
the	O
dialed	O
digits	O
one	O
at	O
a	O
time	O
from	O
reed	B-Algorithm
relay	I-Algorithm
packs	O
to	O
frequency	O
generators	O
,	O
under	O
sequential	O
control	O
of	O
logic	O
implemented	O
with	O
wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
.	O
</s>
<s>
At	O
the	O
other	O
end	O
,	O
similar	O
relays	O
steered	O
the	O
incoming	O
digits	O
from	O
the	O
tone	O
decoder	O
to	O
a	O
reed	B-Algorithm
relay	I-Algorithm
memory	O
.	O
</s>
<s>
Wire	B-Algorithm
spring	I-Algorithm
relays	I-Algorithm
were	O
also	O
incorporated	O
into	O
the	O
signaling	O
channel	O
units	O
of	O
carrier	B-Protocol
systems	I-Protocol
.	O
</s>
