Electret Mic- Phantom Voltage

Electret mics typically depend on "phantom voltage" (typically 12-48v @ very low amps) in the signal wires to power the condenser mics. Does anyone know if there is a standard for this voltage in aviation radios and intercoms?

From David Clark:
"Electrical Specifications?Microphone Model M-7A (P/N 09168P-33)
DC supply voltage and source resistance: 8 to 16 volts, 220 to 2200 ohms-not polarity sensitive. "

For standard headset wiring, I believe ground is sleeve, mic audio (and power) is on the ring.

http://www.rst-engr.com/rst/support/APNOTE02.pdf

More from DC - looks good to go

Thanks Mike - you led me to the answer.

MODEL M-7A ELECTRET MICROPHONE
This David Clark Company Electret Microphone is a noise cancelling type designed to operate in place of carbon and amplified dynamic microphones. This microphone will not operate in circuits that do not supply a DC bias voltage. Most modern aviation communications equipment do supply this required voltage. If you are not certain, consult your radio technical manual or with your avionics shop.