<s>
Microducts	B-Device
are	O
small	O
ducts	O
used	O
for	O
the	O
installation	O
of	O
fibre	B-Architecture
optic	I-Architecture
cables	O
.	O
</s>
<s>
Microducts	B-Device
are	O
typically	O
small-diameter	O
,	O
flexible	O
,	O
or	O
semi-flexible	O
ducts	O
designed	O
to	O
provide	O
clean	O
,	O
continuous	O
,	O
low-friction	O
paths	O
for	O
placing	O
optical	O
cables	O
that	O
have	O
relatively	O
low	O
pulling	O
tension	O
limits	O
.	O
</s>
<s>
As	O
stated	O
in	O
industry	O
requirements	O
document	O
Telcordia	O
GR-3155	O
Generic	O
Requirements	O
for	O
Microducts	B-Device
for	O
Fiber	B-Architecture
Optic	I-Architecture
Cables	O
,	O
microduct	O
products	O
are	O
expected	O
to	O
:	O
</s>
<s>
Therefore	O
,	O
for	O
microducts	B-Device
,	O
air-blown	O
cable	O
installation	O
techniques	O
are	O
expected	O
to	O
be	O
the	O
most	O
useful	O
.	O
</s>
<s>
The	O
first	O
is	O
more	O
common	O
for	O
copper	O
balanced	O
cables	O
;	O
the	O
latter	O
for	O
fibre	B-Architecture
optic	I-Architecture
cables	O
.	O
</s>
<s>
The	O
ducts	O
in	O
which	O
the	O
fibre	B-Architecture
optic	I-Architecture
cables	O
are	O
installed	O
are	O
usually	O
made	O
of	O
polyethylene	O
.	O
</s>
<s>
The	O
installation	O
of	O
fibre	B-Architecture
optic	I-Architecture
cables	O
in	O
ducts	O
can	O
be	O
done	O
by	O
pulling	O
or	O
by	O
cable	O
jetting	O
.	O
</s>
<s>
It	O
is	O
more	O
difficult	O
to	O
make	O
branching	O
fibre	B-Architecture
optic	I-Architecture
networks	O
in	O
the	O
access	O
network	O
than	O
it	O
is	O
for	O
copper	O
balanced	O
cables	O
.	O
</s>
<s>
Splicing	O
optical	B-Architecture
fibres	I-Architecture
is	O
much	O
more	O
difficult	O
than	O
connecting	O
copper	O
wires	O
.	O
</s>
<s>
With	O
microduct	B-Device
cabling	I-Device
,	O
bundles	O
of	O
small	O
microducts	B-Device
may	O
be	O
installed	O
in	O
larger	O
protective	O
duct	O
(	O
e.g.	O
,	O
PVC	O
conduit	O
)	O
.	O
</s>
<s>
Bundles	O
of	O
microducts	B-Device
can	O
also	O
be	O
factory	O
pre-installed	O
.	O
</s>
<s>
The	O
microducts	B-Device
can	O
be	O
branched	O
very	O
easily	O
in	O
the	O
network	O
.	O
</s>
<s>
Possibility	O
to	O
migrate	O
from	O
copper	O
balanced	O
cables	O
to	O
fibre	B-Architecture
optic	I-Architecture
cables	O
.	O
</s>
<s>
Today	O
the	O
microduct	B-Device
cabling	I-Device
technology	O
is	O
used	O
more	O
and	O
more	O
,	O
all	O
over	O
the	O
world	O
.	O
</s>
<s>
The	O
fibre	O
counts	O
have	O
grown	O
up	O
to	O
144	O
per	O
cable	O
and	O
can	O
be	O
installed	O
in	O
microducts	B-Device
of	O
only	O
8	O
mm	O
inner	O
diameter	O
.	O
</s>
<s>
Bundles	O
of	O
microducts	B-Device
can	O
be	O
jetted	O
over	O
1500	O
m	O
or	O
more	O
.	O
</s>
