Multimeter Tests
Copper and G.fast/VDSL2/ADSL2+ Multi-play Test Set
139
Capacitance/Opens
Capacitance/Opens
The
Capacitance/Opens
test measures the electrical capacitance of the
loop and calculates length. Capacitive balance is also measured when all
pairs are selected.
Snapshot
The
Capacitance
/
Opens
test should be run with the far end open, as
electronics and equipment will skew or change the values. DSL splitters
also add some capacitance and change the values, as do some NIDs and
filtered wall plates.
The test gives you a quick indication of the length, to help you see if the
loop is too short and has an open. The capacitive balance is key and should
typically be 95 % (5 % imbalance) for POTS/internet, and better for high
speed broadband such as VDSL2. If the opens distance is significantly less
than indicated on plant maps, then the pair may be open at the distance
suggested. (Of course, if the distance matches the expected length, you are
seeing the end.)
Be a bit cautious with capacitance/opens, as wet faults or physical damage
can significantly change the result. Wetness can provide a path to ground
or other pairs which are then also included in the capacitance value and
not just the pair under test. Opens can usually be located using a TDR.
To access TDR from Multimeter tests:
1.
Press
to return to the
Copper Main
menu.
2.
Highlight
TDR
and press
to open the
TDR
menu.
3.
Select either
Auto TDR
or
Manual TDR
to run the test.
Auto TDR
will
attempt to locate the nearest large event/reflection which may or may
not be the open.
TDR
can also be run from
Pair Detective
.
Summary of Contents for MAX-635G
Page 1: ...User Guide Copper and G fast VDSL2 ADSL2 Multi play Test Set MAX 635G www EXFO com ...
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Page 270: ...TDR 260 MAX 635G Continuous Examples of Common Faults Short Fault ...
Page 271: ...TDR Copper and G fast VDSL2 ADSL2 Multi play Test Set 261 Continuous Open ...
Page 272: ...TDR 262 MAX 635G Continuous Bridged Tap ...
Page 273: ...TDR Copper and G fast VDSL2 ADSL2 Multi play Test Set 263 Continuous Splice Joint ...
Page 274: ...TDR 264 MAX 635G Continuous Peak Function ...
Page 275: ...TDR Copper and G fast VDSL2 ADSL2 Multi play Test Set 265 Continuous Dual Trace View ...
Page 276: ...TDR 266 MAX 635G Continuous Load Coil ...
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