Driving An Led; Logic Input And Output; Push To Talk Microphones - Polycom SoundStructure C16 Hardware Installation Manual

Hardware Installation Guide for the Polycom SoundStructure

Driving an LED

SoundStructure logic outputs can be used to turn on or off LEDs. In this example when the logic output is
driven on (1 or high), current will flow, and the LED will turn on. When the logic output is set off (0 or low),
current will stop flowing, and the LED will turn off.
Most standard LEDs need about 2.0 V to illuminate. In this example a 274 ohm resistor is used to limit the
current from Pin 1.
A series resistor must be used to limit the voltage and current to a safe level for the LED.
Increasing the series resistor value will decrease the current through the circuit and will also decrease the
voltage at the input to the LED, reducing the brightness of the LED.
Driving an LED
Remote Control

Logic Input and Output

Push To Talk Microphones

The SoundStructure devices may be used with push to talk microphones such as the Shure MX392.
When the orange (LED in) wire is connected to ground due to the SoundStructure logic output being turned
on, the LED on the microphone will turn on. The LED is powered from the SoundStructure phantom power
supply on the red and black cables. This means that the LED on the microphone does not need external
power through a pull-up resistor on the orange (LED in) wire. The shield of the cable provides a ground for
the entire audio and logic circuit even though there is a separate green wire for Logic Ground. This means
that the green wire does not need to be connected to SoundStructure device. One could connect the green
wire to the shield at the mic side and then only need to run a 4-conductor cable plus shield to the
SoundStructure device, or one could run the microphone's logic ground to the ground on the logic connector.
Polycom, Inc.
Pin 1 : +5V
Pin 2 : Logic Output 1
LED
274 ohm
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