Shure Four Channel Automatic Microphone SCM410 - Manual (Page 11)

11
SUGGESTED LOGIC APPLICATIONS
This section contains suggestions on the uses of the SCM410's logic
capabilities. Note that uses of these functions are not limited to the listed
applications. The user is limited only by imagination and creativity. For ad-
ditional suggestions and solutions to installation problems, contact the
Shure Applications Department.
COUGH BUTTON
The talker can turn off his or her microphone during coughing or private
conversations by installing an SPST pushbutton switch between the
MUTE IN and Logic Ground pins for each channel to be modified (see Fig-
ure 7). When a channel is muted, no audio is passed. (See Dead Zone on
MUTE IN Defeat paragraph in the Internal Modifications section for more
information on MUTE IN logic.)
CHAIRPERSON-CONTROLLED MUTING
The chairperson can, by activating a switch, silence all other micro-
phones and be heard without interruption. For operation in this mode,
connect all the MUTE IN pins together except that of the chairperson's
channel, and wire an SPST pushbutton or toggle switch between those
MUTE IN and Logic Ground pins (see Figure 8).
An alternative to a switch is to connect the chairperson's GATE OUT
to the MUTE IN of other channels. When the chairperson's microphone
activates, all other microphones mute.
REMOTE CHANNEL-ON INDICATORS
Remote indicators can be used to indicate when a talker's microphone
is on. Connect the LEDs and a 5-volt supply to the GATE OUT pins (See
Figure 9). To avoid switching clicks in the audio output, do not ground the
power supply negative terminal in the audio system or rack ground.
IMPORTANT: If a single cable is used for the microphone audio
signal and the LED dc power, separate shielded pairs must be
used. Failure to carry the dc power on a shielded pair may result in
audible clicking due to capacitive coupling between the dc power
lines and microphone lines.
DISABLING THE GATING FUNCTION (BYPASS)
To keep certain microphones on at all times, wire the desired micro-
phone channel's OVERRIDE IN pins together to the Logic Ground pin.
The selected channels now function as they would in a non-automatic
mixer (see Figure 10). To perform this modification internally on the mixer,
refer to the Shorting Override In to Logic Ground Internally paragraph in
the Internal Modifications section.
M1
M3
M2
COUGH BUTTONS
FIGURE 7
LOGIC
GROUND
M2 M3 M4
CHAIRPERSON-CONTROLLED MUTING
FIGURE 8
LOGIC
GROUND
+
G 1 G 3
470 ,
1/4 W
470
1/4 W
470
1/4 W
G 2
7 7
7
, ,
REMOTE CHANNEL-ON INDICATORS
FIGURE 9
LOGIC
GROUND
5 V POWER
SUPPLY
O2 O1 O3
GATING BYPASS
FIGURE 10
LOGIC
GROUND