The Art & Science of Audio & Video

No Audio – Push to Talk Mic

Q: I have a push to talk mic that I can’t get any audio from. It has a pre-terminated cable attached from the factory. What gives?

A: First things first let’s never assume that we know how any device is wired from the factory. Especially a push to talk microphone! I’ve seen manufacturers that didn’t use consistent wiring schemes throughout their own product line. Refer to your manual to check for any unusual wiring practices. If it appears to be wired in accordance to what has become the accepted norm for these days (Pin1 shield, Pin2 hot and Pin3 negative) then we will proceed to the next step which is the switch for the push to talk feature. PTT mics can come in any number of configurations. Usually the switch is pre-wired and is selectable between ‘normally open’ and ‘normally closed’. If it’s wired as “NO” then when you press the switch it completes the circuit and activates the mic. If it’s wired as “NC” then the mic is constantly on and mutes when you press the switch. Some units also provide an extra pair of conductors in the pre-made cable so that you could connect the switch to an external device. For instance in a paging system you may push the switch to talk, but also want to send a contact closure to a mixer to mute background music as well. Some units with this feature may not have the switch internally wired from the factory meaning the mic will not function until you wire it yourself for the configuration that fits your needs.


February 23, 2008 - Posted by | Troubleshooting | , , , , , ,

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