RTS MCS-325, Руководство пользователя

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34 Operation MCE-325 Programmable User Station
Bosch Security Systems, Inc. Technical Manual F.01U.193.228 Rev. 13
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 MCE-325 can be programmed, via the front panel, so the microphone automatically turns on whenever a
channel is activated for talk. The MCE-325 may also be internally programmed for voice-activated microphone
(VOX) as previously described in “VOX (DS8)” on page 24.
Speaker On/Off
The SPKR ON button turns the external speaker on (LED on) or off (LED off).
Volume Adjustment
Table 12 on page 37 summarizes the operation of the volume controls for the various intercom line configurations. The MCE-
325 is pre-programmed for stereo operation; CH 1 (VOL 1) adjusts the level to the left headphone and CH 2 (VOL 2) adjusts
the level to the right.
NOTE:
•
To use the stereo mode, you must have 5-pin stereo headset.
•
The MCE-325 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 MCE-325 is used with 2-wire lines, the station operator’s voice signal is not only transmitted onto the intercom
lines, but also echoed back into the MCE-325 receive circuits. This can result in acoustic feedback when the MCE-325 is used
with an external speaker. The sidetone nulling trimmers are used to null, or subtract, the station operator’s voice signal from
the rest of the received signal to prevent this feedback.
NOTE: This is not necessary in 4-wire systems since transmit and receive use separate circuits.
A trimmer is provided for each of the four (4) channels. The trimmers are factory-preset for maximum nulling of the
microphone signal when an ideal 200
Ω
resistance terminates each intercom channel; however, the trimmers may require slight
readjustment after the MCE-325 has been installed to compensate for variations from the ideal.
To adjust the sidetone nulling trimmers , do the following:
1.
Turn the speaker switch on (even if an external speaker is not connected).
This turns off the internal, true sidetone trimmer (see note below) .
2.
Turn the microphone on .
3.
Activate one (1) 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 only one (1) 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 turned on to prevent
feedback. See “Headphone Sidetone Trimmer Adjustment (R37)” on page 25 for further details.