Honeywell KMA 28B System Installation And Operation Manual page 16

Bendix/King
KMA 28B Audio Selector Panel and Intercom System
Installation and Operator's Manual
KMA 28B J2, pin M is the passenger hook switch. Install a SPST switch in a location adjacent to each
passenger headset where cell phone use is desired. When pin M is connected to ground through any
switch, the passenger microphones are all on the Com 3/duplex system.
The hook switches are not active or required unless the audio panel is in Com 3 /Duplex mode, with pin J,
J2 grounded.
The wireless communication "TEL" system utilizes an intercom loop. Therefore, any time the cell phone
is in use from the pilot or copilot side, pilot and copilot will lose intercom capability. In the ALL mode,
when the passengers' activate the cell phone, the pilots will have intercom, and continue to hear and
transmit over the avionics normally. However, the passengers will not have intercom, because they are on
the telephone.
D201106000060 Page 2-9 June 2011