Fluke TS53 PRO, Руководство пользователя, Страница: 9 / 38

5
Physical Characteristics
Display and Keypad
See Tables 1 and 2.
The test sets have an LCD display and a keypad that are
recessed into the housing. The recessed bezel protects
the keypad and helps prevent accidental key presses.
Table 1. Display Icons
GOL03.EPS
(
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 29.
TALK Shows when the test set is in Talk mode. See "Talk Mode" on page 12.
MON Shows when the test set is in Monitor mode. See "Monitor Mode" on page 11.
VDC
mA
When the test set is on-hook, it measures the dc voltage (4 V dc to 140 V dc) at the test leads. Normal
line voltage across Tip and Ring is between 42 V dc and 54 V dc.
When the test set is off-hook, the display shows the dc loop current (0 mA to 100 mA) that the test set
draws from the line. 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.
These tests let you quickly see if the line has the correct Central Office battery voltage or the correct
loop current. Voltage below 4 V dc is too low for the test set to go off-hook.

Warning

Voltage above 140 V dc is possibly dangerous to you and the test set. See "High
Voltage Lockout Operation" on page 14.
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