7
Physical Characteristics
TONE/PULSE
The TONE/PULSE key is used to switch between tone and pulse dialing. The TONE/PULSE key is
only active when the test set is off-hook. Any time the test set goes off-hook, it is automatically
set to tone dialing. Once off-hook, pressing the TONE/PULSE key will change the dialing mode
to pulse dialing. Pressing the key again will switch back to tone dialing.
TEST
The TEST key is used to perform two tests. One test is performed when the test set is on-hook
and the other test when the test set is off-hook. The results of the tests are meaningful only if
the unit’s test leads are connected to Tip and Ring of a subscriber line.
When the test set is on-hook, pressing the TEST key causes one of the tests to be executed. The
test set measures the dc voltage across Tip and Ring and then displays, by LED, whether the
voltage is high, low, or normal. The test is designed to indicate dc voltage on the line under test
(see “HI/LO Voltage LEDs” for a description of the indications). For example, the user runs the
test, expecting a normal battery voltage of -48 Vdc on a particular line, instead, the amber LED
flashes indicating the dc voltage is lower than a normal CO battery. This tells the user that they
may be connected to the wrong pair and should further investigate why the battery on the line
under tests is not normal.
The POL LEDs double as low loop current indicators. When off-hook and the TEST key is
pressed, if the current reading is below 23 mA, the LED corresponding to the line polarity will
flash for 5 seconds. If the loop current is normal, the LED will light solid. Low loop current may
indicate a problem on the line.
Light Emitting
Diodes (LEDs)
All LEDs are located on the keypad inside the recessed area.
MUTE LED
The MUTE LED flashes when the mute function is activated.
LO BATT (Low
Battery) LED
The LO BATT LED flashes when the 9 V battery is nearly discharged. The low battery LED is active
only in operating modes that use the battery.
POL LED
Notes
The TS42DLX Deluxe Test Set is not polarity sensitive, and will function in either polarity.
The POL LEDs will not light if the test set is on-hook or when the speaker is on.
When the test set is off-hook, one of the two Polarity (POL) LEDs will illuminate automatically to
indicate the dc polarity of the line. The green POL LED will light if the red test lead is connected
to the Ring (negative) side of the line and the black test lead is connected to the Tip (positive)
side of the line. The red POL LED will light if the test leads are reversed; that is, with the red test
lead connected to the Tip (positive) side and with the black test lead connected to the Ring
(negative) side.
LO mA LED. The POL LEDs double as low loop current indicators. When off-hook and the TEST
key is pressed, if the current reading is below 23 mA, the LED corresponding to the line polarity
will flash for 5 seconds. If the loop current is normal, the LED will light solid. Low loop current
may indicate a problem on the line.
Electronic
Ringer
The electronic ringer is enabled while the test set is on-hook.
-continued-
Table 2. Test Set Keypad Control and Indicators (continued)
Key or Indicator
Description (see Figure 3)
