PairGain PG-Flex, Manual

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Guidelines to Preprovisioning HDSL Lines
25
Guidelines to Preprovisioning HDSL Lines
The HDSL transmission scheme uses two-wire pairs between the Central Office Terminal (COT)
and the Remote Terminal (RT). The wire pairs should have identical electrical make-ups. Keep
exposure to crosstalk and the differences in total wire length, wire gauge, and bridge taps to a
minimum. Pair isolation (Tip-ring, Tip-ground, and Ring-ground) must be 100 k
Ω
.
The wire pairs from the COT to the RT must meet the following design guidelines (use local
practices to determine the guidelines listed below):
• nonloaded cable only
• multi-gauge restricted to two gauge changes, except for stubbing or fusing
• total bridge taps can not exceed 2.5 kft. No single bridge tap may exceed 2.0 kft
The distance limitation for HDSL transmission is based on a maximum signal attenuation of 35 dB
at 196 kHz. Since signal attenuation decreases as cable size increases, the larger the gauge
(that is, 19 AWG vs. 26 AWG), the greater the distance between the COT and the RT. Table 9
identifies these distances at a cable temperature of 68°F.
The HDSL line should be preprovisioned before installing PG-Flex equipment. Use local
practices for installation/turn-up of HDSL lines.
Table 9. 12/24 Channel HDSL Transmission Distance
Gauge Loop Length DC Resistance
19 AWG
0.9 mm
22.8 kft
7.0 km
367
Ω
22 AWG
0.6 mm
16.1 kft
4.9 km
521
Ω
24 AWG
0.5 mm
12.3 kft
3.7 km
638
Ω
26 AWG
0.4 mm
9.0 kft
2.7 km
750
Ω