12
Using the Test Set for Troubleshooting Circuits
Some general troubleshooting procedures and tips are provided here. These procedures may
require other tools or equipment that are specific to the communications system installation
trade. For a complete selection of VDV (voice-data-video) tools, please refer to a Greenlee full-
line catalog, a Greenlee/Tempo VDV catalog, or visit our website at www.tempo.textron.com.
Ground fault Check for the presence of voltage. If voltage is
present, measure the level. If it is typical line
voltage, contact the local electric utility.
A long run of telephone
cable near a power line
Contact the local electric utility.
Power hum Cable imbalance Break the circuit down into sections and check
each section for an imbalance.
Momentary or impulse
noise
This may be due to an unbalanced cable, nearby
power switch gear, or similar equipment.
Popping, crackling The customer has an older carbon transmitter
type of telephone.
Noise Hiss (white noise);
pulse dialing causes a
momentary change in
the sound of the noise
This is probably due to water in the cables.
Cross connection Direct wiring fault Check for crossed pairs.
Cross-talk Split pair A split pair (a circuit made up of wires from two
separate wire pairs) will be unbalanced and
prone to cross-talk.
Symptom*
Possible Cause /
Troubleshooting Step
Explanation
This is a potentially hazardous situation!
If the test set produces the excessive DC
voltage alarm
(low pitch, low pitch, low pitch)
or the AC line voltage alarm
(constant ringing),
remove the test set from the line carefully and
immediately!
Test set alarms Telephone wire
contacting a power
line
*Wet cables may cause most of these symptoms and may cause multiple symptoms to appear
at the same time.
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