5
Physical Characteristics
Table 1. Test Set Audio Control Keys
Key
Description (refer to Figure 2)
MUTE
The MUTE key functions only when the test set is off-hook. When the test set is off-hook and being
used as a handset, pressing the MUTE key shuts off the handset’s microphone. This is useful in noisy
environments such as near heavy traffic. With the mute on, ambient noise is not picked up by the
test set’s microphone and therefore not transmitted to the speaker. 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 turns 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 12.
When the mute is on, the MUTE LED flashes.
VOL
(Volume)
Pressing the VOL key switches the active receiver’s sound level between normal and high volume.
This occurs in Monitor mode and Talk mode. The state of the VOL key is preserved when the active
receiver is changed. For example, with the handset receiver volume set to high, if you switch to the
speaker, it will also be set to high volume. The VOL key affects only the volume of received signals. It
does not affect the volume of transmitted signals.
SPKR
(Speaker)
The SPKR key turns 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 turns on the
speaker. This lets you 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 turns 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 12). 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 turns on the Receive
Only Loud Speaker. This mode is intended for listening to the line, hands free.
