Connecting the headset, turning on the battery pack Connect the XLR-3 plug of the headset connecting cable to the XLR-3 socket on the connecting cable of the battery pack. HMEC 350 and HMEC 450 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. HMEC 355-C headset: Connect the XLR-5 plug for the headphones and the microphone to the aircraft�s XLR-5 socket. HMEC 372 and HMDC 372 headsets: Connect the U-174/U jack plug for the headphones and the microphone to the U-174/U socket of your intercom. Turn on the battery pack by setting the ON/OFF switch to ON. The yello LED power indicator lights up. Note: When using the battery pack, the ON/OFF switch integrated into the headset connecting cable is out of operation. Attaching the battery pack to clothing The battery pack can be attached to clothing by means of the supplied attachment clip, Velcro tape is also supplied.
