ADTRAN 1245001L6, Руководство по установке и обслуживанию

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16 Section 61245001L6-5, Issue 7 61245001L6-5G
6. HDSL DEPLOYMENT GUIDELINES
The ADTRAN HDSL system is designed to provide
DS1 based services over loops designed to comply
with carrier service area (CSA) guidelines. CSA
deployment guidelines are given below.
1. All loops are non-loaded only.
2. For loops with 26-AWG cable, the maximum
loop length including bridged tap lengths is 9
kft.
3. For loops with 24-AWG cable, the maximum
loop length including bridged tap lengths is
12 kft.
4. Any single bridged tap is limited to 2 kft.
5. Total bridged tap length is limited to 2.5 kft.
6. The total length of multi-gauge cable
containing 26-AWG cable must not exceed
the following:
12 - {(3*L
26
)/(9} - L
BTAP
)} (in kft)
L 26 = Total length of 26-AWG cable
excluding bridged taps (in kft)
L
BTAP
= Total length of all bridged taps (in kft)
This deployment criteria is summarized in the chart
shown in
Figure 17
.
Loop loss per Kft for other wire is summarized in
Table 7 .
Recommended maximum local loop loss
information for PIC cable at 70
°
F, 135
Ω
, resistive
termination is provided in Table 8 .
An approximation for the maximum amount of
wideband noise on an HDSL local loop as measured
by a 50 kbps filter is
≤
31 dBrn.
An approximation for the maximum level of
impulse noise as measured using a 50 kbps filter on
an HDSL loop is
≤
50 dBrn.
NOTE
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
-7
BER.
Table 7. HDSL Loss Values
(200 kHz cable loss in dB/kft at 135
Ω
)
Cable Gauge
26
26
24
24
22
22
19
19
Cable Type
PIC
Pulp
PIC
Pulp
PIC
Pulp
PIC
Pulp
Temperature
68
°
90
°
120
°
3.902 4.051 4.253
4.030 4.179 4.381
2.863 2.957 2.083
3.159 3.257 3.391
2.198 2.255 2.333
2.483 2.450 2.629
1.551 1.587 1.634
1.817 1.856 1.909
Table 8. Loop Insertion Loss Data
Frequency
(Hz)
3000
10,000
50,000
100,000
150,000
196,000
200,000
Maximum Loss
(dB)
12.0
15.0
25.5
30.0
32.75
35.00
35.25
Figure 17. HDSL Deployment Guidelines
0
12
11
10
9
8
7
6
5
4
3
2
1
0
1 2 3 4
WORKING LENGTH OF 26 GAUGE CABLE (KFT)
WORKING LENGTH OF 24 GAUGE (OR COARSER) CABLE (KFT)
5 6 7 8 9
2.5
INVALID HDSL CABLE LENGTHS
2.0
1.5
1.0
0.5
0.0
TOTAL
BRIDGED
TAP
LENGTH
(KFT)
VALID HDSL CABLE LENGTHS