The XLR-5 connector is a single connector that can be used in place of the PJ055 headphone and the PJ068 microphone plugs on some Sennheiser headsets.
Pin 5 of this plug can also be used to provide aircraft power for the NoiseGard power supply on some Sennheiser headsets.
Pin 5 of this plug can also be used to provide aircraft power for the NoiseGard power supply on some Sennheiser headsets.