Polycom SR12, C12, C16, C8 manual Logic Input And Output, Push To Talk Microphones

Hardware Installation Guide for the Polycom SoundStructure C16, C12, C8, and SR12

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.

No current-limiting resistors are needed between the microphone and the SoundStructure device as the current on the Orange (LED IN) wire when the LED is on is on the order of microamps.

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