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Bendix/King
KMA 28B Audio Selector Panel and Intercom System
Installation and Operator’s Manual
D201106000060
Page 2-8
June 2011
2.5.4
Marker Audio Input (non-marker version)
If using an external marker receiver, the audio input is J1, pin 21 (MKR input).
2.6
Adjustments
The KMA 28B is factory adjusted to accommodate the typical requirements for most aircraft configura-
tions. There are five adjustments however, that will allow the installer to tailor the specific functions.
Unswitched input #3 can be attenuated by adjusting VR1 and COM 3 volume (for cellular phone volume)
is adjusted with VR73. Both are located on the bottom board, accessible through the top board. The unit
will have to be removed from the tray to make these adjustments.
Figure 2-3- KMA 28B Adjustments
2.7
Communications Antenna Installation Notes
For best results while in Split Mode, it is recommended that the one VHF communications antenna is lo-
cated on top of the aircraft while the other communications antenna is installed on the bottom. Any an-
tenna relocation must be accomplished in accordance with AC 43.13-2A, aircraft manufacturers’ recom-
mendations, and FAA-approved technical data.
Warning
:
It is probable that radio interference will occur in the split mode when the frequencies of the two air-
craft radios are adjacent, and/or the antennas are physically close together.
Honeywell makes no ex-
pressed or implied warranties regarding the suitability of the KMA 28B in Split Mode.
2.7.1
Hook Switches
While the Com 3 button acts as the hook switch for the pilot, additional hook switches must be installed to
have full access to the cell phone system. The copilot hook switch is a SPST switch that connects pin L of
J2 on the KMA 28B to ground to place the copilot mic audio on the Com 3 audio in duplex mode for cell
phone operation.
Com 3
Volume
Speaker
Volume
Marker
Volume
Marker
Gain LO
Marker Gain-
HI