5
Physical Characteristics
Table 1. Test Set Audio Control Keys
Key
Description (see Figure 2)
MUTE
The MUTE key is functional only when the test set is off-hook; it has no function when the unit is
on-hook. When the test set is off-hook and is being used as a handset, pressing the MUTE key will
shut off the handset’s microphone. This is useful in noisy environments such as near traffic. With
the mute on, ambient noise is not picked up by the test set’s microphone and therefore does not
end up in the operator’s ear. When the mute is on, it is easier to hear the person at the other end
of the line and easier to hear static or noise on the line. Pressing the MUTE key again will turn the
microphone on.
When the test set is off-hook and is in Speakerphone mode, pressing the MUTE key will shut off
the speakerphone’s microphone and will put the test set into a Receive-Only Loud Speaker mode.
This is a better mode for troubleshooting than Speakerphone mode. Pressing the MUTE key again
will turn the speakerphone microphone on.
The test set may be configured to operate exclusively in Receive-Only Loud Speaker mode. When
in this mode, the MUTE key has no effect on test set operation while in loudspeaker mode. See
“Configuring Your Test Set” on page 10.
When the mute is on, the MUTE LED will flash.
VOL
(Volume)
Pressing the VOL key switches the sound level of the test set’s active receiver between normal and
high volume. This is true in Monitor mode as well as Talk mode. The state of the VOL key is
preserved when the active receiver is changed. For example, assume the handset receiver is set to
high volume, if you switch to the speaker, it will also be set to high volume. The VOL key only
affects the volume of received signals. It does not affect the volume of transmitted signals.
SPKR
(Speaker)
The SPKR key is used to turn the test set’s speaker on and off. It functions in both Talk and Monitor
modes.
In Monitor mode, if the test set is being used as a handset, pressing the SPKR key will turn on the
speaker. This allows a user to monitor a line while working at a distance from the test set.
If the test set is off-hook and is being used as a handset, pressing the SPKR key will turn on the
Speakerphone. The handset microphone and receiver are shut off and the speakerphone
microphone and speaker are enabled. This mode is intended for two-way, hands-free
conversation.
You may also configure the test set to operate exclusively in Receive- Only Loud Speaker mode (see
“Configuring Your Test Set” on page 10.) For test sets configured as Receive-Only Loud Speaker; if
the test set is off-hook and is being used as a handset, pressing the SPKR key will turn on the
Receive- Only Loud Speaker. This mode is intended for listening to the line, hands free.
