January/February/March 2020 I 39
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2
1
4
2
3
1 2
9 10 3
12 11 4
6 5
8
7
1
6 2
3
4
5
7
2 Tube
4 Tube
7 Tube
12 Tube
Date Issued: 03/18
Revision: 15
19
2 3
11 10 9
10 19
12
13
14
1
17
24
21 20
22
15 16
23
4
18
5
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2
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4
5
6
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18
8
9
12
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15
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17
11
19 Tube
24 Tube
FIGURE 4: Tube cable 2-to-24 configurations. Some customers
leave tubes empty for future expansions and upgrades.
Tube cables generally range from
2-to-24-tube cable options as shown
in Figure 4.
Tube distribution units (TDUs)
are installed at strategic locations to
connect the tube cable and can also
be the point of transition to another
branching location. At the TDU
transition point, there are many
applications that can be deployed,
such as making nondisruptive moves,
adds, and changes (MACs), distributing
from larger count tube cable to
smaller counts and also transitioning
through environments of differing
cable jacket ratings, such as an out-
side plant to riser or plenum. This
transition is done by coupling tubes
FIGURE 5: Tube cables are joined in the TDU
using push-fit connectors. Splices, the most
common site of network failure, are virtually
eliminated allowing point-to-point connectivity
in the network.
FIGURE 6: The blowing equipment setup.
together and allows for a
continuous point-to-point
and end-to-end fiber bundle
blow without any fusion
splicing, thereby eliminating
potential points of
network failure (Figure 5).
Once the complete
(approximately 4,300 meters), and
48 and 72-strand up to 10,500 feet
(approximately 3,200 meters). Once
the tube cable is in place, the fiber
bundles are then blown into the
tubes using only two installers. The
process of blowing the fiber is done
using special blowing equipment
and safe nitrogen gas or compressed
air (Figure 6).
infrastructure pathway is installed
with the tube cable, a pressure test
must be performed to ensure the
integrity of the tubes as well as an
obstruction test assuring that there
is no possible obstruction. Singlemode
(OS2) 2, 4, 6 and 12-strand
can be ordered in lengths up to
39,000 feet (approximately 12,000
meters), 24-strand up to 14,500 feet