8
TS52PRO Test Set
Users Guide
Vdc/mA TEST
key
When you press the
Vdc/mA TEST
key, one of two tests is performed depending on the
operating mode of the test set. If the test set is in Monitor mode and you press the
Vdc/mA TEST
key, the Vdc (dc voltage) test will be executed. If the test set is in Talk mode (off-hook) and you
press the
Vdc/mA TEST
key, the mA test (loop current) will be executed.
To run the Vdc test, put the test set into Monitor mode and connect it to Tip and Ring of the
POTS line you want to measure. Then press the
Vdc/mA TEST
key. The test set measures the dc
voltage across Tip and Ring and the measured voltage (0-140 Vdc) is shown on the display.
Normal line voltage is between 42 and 54 V dc.
To run the mA test, connect the test set to Tip and Ring of the POTS line you want to measure
and take the test set off-hook. Then press the
Vdc/mA TEST
key. The test set measures the dc
loop current that it is drawing from the line. The measured current (0-120 mA) is shown on the
display. Normal loop current is above 23 mA. If the loop current is too low, the telephone line
you are testing may not be able to supply enough current to power the customer’s telephone
devices and you may want to perform some additional testing on that line.
The purpose of these tests is to allow you to make a quick assessment of whether or not the line
you are working on has normal CO battery voltage or normal loop current. If the voltage is
below 2.5 V dc, there is not enough voltage for the test set to go off-hook. If the voltage is
above 140 V dc, this is potentially dangerous to you and the test set. If you encounter this,
carefully remove the test set’s clip leads from the line. Be sure to hold the clip leads by their
insulated boots and avoid touching the clip lead’s metal parts with your hands. Be careful to
avoid shorting the clip leads to each other. See "High Voltage Lockout Operation" on page 13.
Low Battery
icon
When the 9 V battery is nearly discharged, no bars are shown on the battery icon on the display.
Replace the battery immediately when this occurs. See "Replacing the Battery" on page 17.
Polarity
icon
The polarity icon indicates the polarity of the dc voltage across the line’s Tip and Ring wires is
reversed. If the test set’s red clip lead is connected to a more positive voltage than its black clip
lead (reverse polarity), the icon is shown on the display. If the test set’s red clip lead is connected
to a more negative voltage than its black clip lead, no icon is shown.
On-Hook / Off-
Hook
icon
The icon indicates which mode the test set is in. The icon will alternate between on-hook and
off-hook when a call is coming in.
Mute
icon
The icon indicates that the
Receive-Only Loud Speaker
mode is on or the test set is muted. See
"Make Receive-Only Loud Speaker the Default" on page 15.
-continued-
Table 2. Display and Keypad (continued)
Key or
Indicator
Description (refer to Figure 3)
