3
Physical Characteristics
Mode Controls
See Figure 2.
The TALK/MONITOR switch is on the inside of the hand
grip near the transmitter. It puts the unit on-hook
(Monitor mode) or off-hook (Talk mode).
The TONE/PULSE switch is on the inside of the hand
grip near the receiver. This switch selects the dialing
mode.
bfw02.eps
Figure 2. Controls and Indicators
Keypad
See Figure 3.
The TS120 Test Telephone keypad includes 12 standard
dialing keys and 4 special purpose keys. All keys on the
keypad are functional when the unit is in the Talk
mode. They are not functional when the unit is in the
Monitor mode.
bfw03.eps
Figure 3. Keypad
MUTE: Pressing the MUTE key shuts off the TS120
transmitter for as long as the key remains depressed.
POLAR: When an off-hook unit is connected to a
powered telephone line, pressing the POLAR key
causes one of the LEDs to turn on. The LEDs indicate
the polarity of direct current on the telephone line.
FLASH: Pressing this key will cause a timed interruption
of the loop current. Some PBX setups or telephone
office switches may use this signal to put a call on hold
or to activate some special function.
REDIAL: This key allows the user to redial the last
number dialed.
Dialing Keys
See Figure 3.
When the TONE/PULSE switch is in the TONE position,
each of the 12 dialing keys, when pressed, generate
dialing tones. This includes the asterisk (
∗
) and the
pound (#) keys. When the TONE/PULSE switch is in the
PULSE position, only the numeric keys (1, 2, 3, 4, 5, 6, 7,
8, 9, 0) will cause pulses to be generated when pressed.
In Pulse mode, the asterisk and pound keys are not
functional. In Pulse mode the asterisk and pound keys
will not be stored in the redial memory.
The special purpose keys are labeled MUTE, POLAR,
FLASH, and REDIAL.
Light Emitting Diodes (LEDs)
See Figure 3.
The LEDs are on each side of the keypad. One or the
other of the LEDs will light only when the test set is in
the Talk mode, connected to a powered telephone
line, and the POLAR key is pressed. The LEDs indicate
the polarity of current on the transmission line. See
“Polarity Check”.
