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Recommended maximum local loop loss information
for PIC cable at 70°F, 135 Ω, resistive termination is
provided in Table 4 for the first segment of the
circuit.
Table 4. First Segment Loop Insertion
Loss Data
F
e r
q
u
e
n
c
y
(
H
) z
3
0 ,
0 0
0 1
0 ,
0 0
0 5
0 ,
0 0
1
0 0
0 ,
0 0
1
0 5
0 ,
0 0
1
6 9
0 ,
0 0
2
0 0
0 ,
0 0
2
0 5
0 ,
0 0
3
5 2
0 ,
0 0
Table 5 provides local loop loss information for the
second segment of the circuit.
Table 5. Second Segment Loop Insertion
Loss Data
F
e r
q
u
e
n
c
y
(
H
) z
3
0 ,
0 0
0 1
0 ,
0 0
0 5
0 ,
0 0
1
0 0
0 ,
0 0
1
0 5
0 ,
0 0
1
6 9
0 ,
0 0
2
0 0
0 ,
0 0
2
0 5
0 ,
0 0
3
5 2
0 ,
0 0
An approximation for the maximum amount of
wideband noise on a DSL local loop as measured by a
50 kb filter is ≤ 31 dBrn.
An approximation for the maximum level of impulse
noise as measured using a 50 kb filter on a DSL loop
≤
is
50 dBrn.
These approximations are to be used as guidelines
only and may vary slightly on different loops.
Adhering to the guidelines should produce
performance in excess of 10
6
M
a
i x
m
u
m
L
o
s
s
d (
B
)
2 1
0 .
5 1
0 .
5 2
5 .
0 3
0 .
3
. 2
5 7
5 3
0 .
3
. 5
5 2
7 3
5 .
4
. 2
0 0
M
a
i x
m
u
m
L
o
s
s
d (
B
)
1
. 1
5 2
1
. 3
0 5
2
. 2
5 7
2
. 6
5 7
2
. 9
0 0
3
. 1
5 2
3
. 1
0 5
3
. 3
5 7
3
. 7
0 0
-7
BER.
5. MAINTENANCE
The ADTRAN 239 H2R requires no routine
maintenance. In case of equipment malfunction,
perform an in-band loopback from the central office
(CO), as defined in Appendix A. If a malfunction is
confirmed, replace the unit.
The ADTRAN 239 H2R has looping capability
through the channel allowing digital loopback in fault
isolation. The looping is accomplished remotely as
defined in Appendix A of this practice.
Performance monitoring, diagnostics, and loopbacks
are also available from the craft interface at the
H2TU-C and H2TU-R.
When testing indicates a faulty circuit pack, refer to
the housing installation/maintenance practice for the
entry and pressurization control, then replace the
faulty circuit pack.
ADTRAN does not recommend field repair of this
unit. Repair services may be obtained by returning
the defective unit to the ADTRAN Customer and
Product Support (CAPS) Department.
61221045L2-5A
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