button action can be changed, via the front panel programming, so that the button controls talk only, with listen either always on or always off.
Panel Mic/Headset Mic Selection
The PANEL MIC button selects either panel microphone (LED on) or headset microphone (LED off).
Microphone On/Off
The MIC ON button turns the microphone on (LED on) or off (LED off).
NOTE The MCE325 can be programmed, via the front panel, so that the microphone will automatically turn on whenever a channel is activated for talk. The MCE325 may also be internally programmed for
Speaker On/Off
The SPKR ON button turns the external speaker on (LED on) or off (LED off).
Volume Adjustment
Table 3.1 summarizes the operation of the volume controls for the various intercom line configurations. The MCE325 is
NOTE The MCE325 can be programmed, via the front panel, for monaural operation if desired.
The PGM VOL control adjusts the monaural mix of both program inputs to both headphones and to the external speaker. It does not affect the program volume on the intercom lines.
Front Panel Sidetone Nulling Trimmer Adjustment
When the MCE325 is used with
To adjust the sidetone nulling trimmers:
1Turn the speaker switch on (even if an external speaker is not connected). This will turn off the internal, true sidetone trimmer (see note below).
2Turn on the microphone.
3Activate one talk button at a time, and speak into the microphone. Slowly increase the volume, and note the level of your voice in the headphones or speaker. Adjust the corresponding sidetone nulling trimmer to minimize your voice signal. Repeat for each channel being used, making sure that only one channel is activated at a time.
NOTE There is also an internal, true sidetone trimmer, which allows the station operator to hear his or her voice when using headphones. This sidetone signal is turned off when the speaker switch is