static” troubles with the Model 3300’s IFD Mode:
1.
Disconnect
at the lightning protector on the subscriber
end.
2.
Confirm the trouble.
Connect a butt set, turn the speaker
on and listen to the line. Confirm that the trouble you hear
(if any) is what the customer reported.
3.
Turn the butt set to mute, and dial a silent termina-
tion.
This is done to prevent any noise picked up by the
microphone of the butt set to be put on the line, as it may
affect the TDR waveform.
4.
Connect the Model 3300.
Connect the test probe leads
to the pair under test. Continue to keep the butt set con-
nected to the pair with the silent termination.
5.
Switch on the TDR
by touching the I/O key.
6.
Initiate the IFD mode
by cycling through the various
display modes.
7.
Wait for the fault to occur.
The Model 3300 will dis-
play a live waveform, while monitoring the line for any
intermittent waveforms. If an intermittent fault occurs, the
trace of the fault area will be superimposed on the live
waveform. With the loop current on line, the trouble will
normally appear within 5 to 10 minutes. Adjustment of the
waveform on the screen both vertically and horizontally
will not affect the test.
Note: Some intermittent faults are caused by the environ-
ment. For these situations it is not necessary to have ac-
cess to a dial tone.