Motorola T3 Betriebsanweisung PDF herunterladen (Seite 19)

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If wire pairs are shorted on any product, line power will be disabled. With the T3, a wire short can

be difficult to detect due to the method of power generation. On XLP products, wire shorts are

easily identified.

T3 PowerBroadband

Cmd: show interface dsl status

This one command provides most of the details you will need to diagnose T3 systems. Copy the

output of this command to notepad for further analysis. In the notes below, different parameters

reported by this command are referenced.

Watch the value of the “line current” parameter. If a wire pair is shorted together, the current will

show “shutdown”. If a wire is shorted to another wire or to ground, the port will draw additional

current, but may not shut down.

For similar distance wires, the line current value should be within 20 points of each other. Note

that in the T3, line power is highly adaptive and variable, so a 20 point delta between adjacent

lines is not necessarily a short.

Check the wire termination and cross connect blocks for split pairs, or double punches (two wires

punched on the same termination lug). Another common source of wire shorts is the RJ11 jack

itself. Often, these can be very old and poorly installed years ago. If a line is not operating

properly, check the RJ11 carefully for signs of corrosion. Remove the RJ11 jack and re-terminate

the screw terminals on the back of the jack.

Line current is an 8-bit number from 255 to 0 that shows the total power consumed by the port,

including power losses in the transmission line. A value of 255 means minimum power, whereas

a value of 85 is the maximum allowed for any single port. The following chart is based on

analysis of typical installations where the wire distance is known.

To determine the power for a single line use the following chart:

Line Current Value Watts ~Distance Note

255 2.58 0 Idle, no load or short wire attached

- -

175 5.38 2m (6ft) 2 x 100Mb load

- -

160 5.82 150m (500ft) 2 x 100Mb load – typical for most hotels

- -

140 6.40 300m (1kft) 2 x 100Mb load– typical for most hotels

- -

95 8.47 600m (2kft) 2 x 100Mb load

- -

85 9.13 Maximum power allowed per line

50 12.36

Out of spec, line will shutdown

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Motorola T3 Betriebsanweisung Seite 19