Appendix A - Functional Description

LTPH-UM-1234-01

 

 

Table 8 on page 26 provides a guide for the loss that occurs when using various cable gauges at 196 kHz and 135Ω . It applies to the HDSL cable pairs between the COT and the HDU, and between the HDU and the RT.

To achieve optimum performance, make the electrical length (196 kHz loss) of all HDU spans as close to equal as possible. This results in the highest operating loop margins. If it is not possible to make all spans equal, choose span lengths that reduce the total power consumption of the CPT that powers the HDU. Do this by minimizing the length of Span 1 and Span 2. Use Table 8 on page 26 when you calculate the electrical length of each span.

The HDU-409 has a range of up to 35 dB loss at 196 kHz on each of the four HDSL loops. A list of HDSL signal cable losses for various cable gauges at 196 kHz and 135Ω is provided in Table 8. The table is applicable to HDSL cable pairs running between the HLU and the HDU-409 and between the HDU-409 and another HDU or HRU.

Table 8.

HDSL Signal Cable Loss

 

 

 

 

Cable Gauge

Ω

per kFt

Loss @ 196 kHz

(0.3048 km)

(dB per kFt) (a)

 

 

 

 

26 AWG/0.4 mm

83.3

3.880

24 AWG/0.51 mm

51.9

2.841

22 AWG/0.61 mm

32.4

2.177

19 AWG/0.91 mm

16.1

1.535

 

 

 

 

(a)Add 3 dB for each bridged tap and 1 dB for each cable gauge change.

26

April 30, 2003

HDU-409 Lists 1, 2, and 3