Sennheiser NoiseGard HMDC 322 Instructions For Use Manual page 51

Power supply for
NoiseGard™
Ground
Do not connect !
XL R-3 socket
14
1. Connecting the headset to the on-board system
The NoiseGard™ electronics can be connected to on-board power supply systems with
operating voltages between 12–35 V DC.
Danger of short circuit!
Before turning on NoiseGard™, ensure that the on-board power supply system is
protected by a 1 A fuse.
The HMEC 300, HMEC 305-C, HMEC 322, HMEC 400 and HMDC 322 headsets are supplied
with an XLR-3 socket for panel mounting in the aircraft. The XLR-3 socket must be
mounted by a technician qualified to perform this type of installation.
HMEC 300 and HMEC 400 headsets:
Connect the ¼" (6.35 mm) stereo jack plug for the headphones and the PJ-068 jack
plug for the microphone to the corresponding jack sockets of your intercom.
Connect the XLR-3 plug to the XLR-3 socket.