Shure Four Channel Automatic Microphone SCM410 - Manual (Page 13)

13
INHIBIT FUNCTION
For information on the inhibit function, refer to the Internal Modifica-
tions section.
REMOTE VOLUME CONTROL
The level of the Aux or Master output can be controlled from an exter-
nal VCA (Voltage Controlled Amplifier) such as the RU-VCA1 from Radio
Design Labs (Tel. 1-800-281-2683, or www.rdlnet.com). To connect a
VCA to the SCM410, proceed as follows:
1.
Connect the SCM410 Line output to the VCA line input.
2. Connect the VCA line output to the external device.
3. For remote Master level control, set the SCM410 Master control
to 5.
DIODE ISOLATION OF LOGIC CONTROLS
Two or more control functions that use the same logic pins can be iso-
lated with diodes, as shown in Figure 14. With this modification, a chan-
nel can be muted by an overall group mute switch, or by its own cough
button.
EXTERNAL LOGIC DEVICES
SCM410 logic levels are directly compatible with TTL and 5V CMOS
logic families. Mixer logic may be used with 15V CMOS logic if a pull-up
resistor is used with each GATE output. See Figure 15.
NOTE: For information on logic gate use, refer to the TTL
Cookbook and CMOS Cookbook, both by D. Lancaster, Howard
Sams Publishing Co.
DIGITAL CONTROLS OR MICROCOMPUTERS
The SCM410 logic pins can interface with custom-designed digital
control circuitry or microcomputers for unlimited possibilities of system
control functions.
M1
M3
D D
DIODE ISOLATION OF LOGIC TERMINALS
FIGURE 14
LOGIC
GROUND
GROUP
MUTE
COUGH
BUTTONS
D = 1N4148 OR
EQUIVALENT
+
–
5.1 K
G1
M1
O1
15V CMOS
FIGURE 15
LOGIC
GROUND
CMOS
GATES
15 V
POWER