SAGEM 3P@C

1.1.1.70Testing the VDSL Subscriber Line

There are certain requirements of the VDSL service commissioning on the subscriber lines:

„The DC loop resistance is required not more than 300 Ω.

„The nominal resistance (the AC resistance between twisted pairs) of lines is 100Ω, and the error is required to be not more than 10%.

„The lines cannot be attached with loading coils, and the practice of attaching the loading coils on the subscriber line is rare in China.

„Better to use twisted pairs (paralleled iron wires and aluminium wires should not exceed 20 m).

„There are no special requirements for the shielding of lines; in principle, there should not exist the bridged tap.

„It is recommended to use in community, buildings or new branch offices but not in large central offices, factories and roadside.

„After the disconnection of Line A and B, the Line A-B, Line A/B-ground AC/DC voltage is about 0V, and the result of below 1V is normal in the test by means of multimeter or 112 test terminal.

„The Line A-B insulation resistance and the Line A/B-ground should be more than 5M?.

„The length of subscriber lines can be basically calculated according to the inter-line capacitance of 50Nf/km, or the loop resistance. The DC resistance reference value of the common lines is shown in the table below:

Table 12-11 DC resistance reference value of common lines

Diameter (mm)

0.32

0.4

0.5

0.6

0.8

DC resistance

236

148

95

65.8

36.6

(Ω/km)

 

 

 

 

 

Before the subscriber line is commissioned, check the quantity of devices being connected in series and parallel on the house line, such as telephones, fax machines, charge registers, extensions of telephone, audio Modem, and IP dialer, and make the detailed records for locating problems in maintenance.

1.1.1.71Connection, Configuration and Commissioning of User End Devices

1) Connection splitter

The VDSL service is the traditional voice and data services run on a twisted pair, requiring the installation of splitter at the user end to split voice from data. The correct installation of VDSL splitters is a key step in the process of VDSL service commissioning.

The house line should be first connected into the Line port of the VDSL splitter, and all the voice devices should be connected to the Phone port of the splitter and VDSL Modem to the Modem port.

The practice of connecting to any voice devices before the Line port of the splitter should be prohibited, or else, Modem cannot work

Note normally.

The method for correctly connecting the splitter is shown in the figure below:

3P@C Installation Manual

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