Existing Gma340 Installation; Power; Audio Panel Interface; Transmit Interlock - Honeywell Bendix/King KMA 30 Manual

Radiated signals can be a factor when low level microphone signals are "bundled" with current carrying
power wires. Keep these cables physically separated. It is very important that you use insulated washers to
isolate the ground return path from the airframe to all headphone and microphone jacks.
2.4.1.1 Music Inputs and Noise
KMA 30 units utilize a differential input to help prevent noise from entering the music system. This fea-
ture is usually transparent to the installer; however, it is important that the appropriate music signal and
ground connections are made directly to the dedicated music signal and ground inputs on the KMA 30.
The power for IFE and audio panel should be a common bus.
If a music jack instead of a music source is installed for Music 1 or 2, we recommend grounding the jack
to airframe ground.
Adding a high-performance audio control system, particularly in conjunction with high-performance ac-
tive noise canceling headsets, cannot improve on older avionics that were designed for cabin-speaker use.
Bendix/King makes no claim that the audio panel will provide a noise-free audio quality under all instal-
lation conditions, particularly with older avionics.
2.4.2

Existing GMA340 Installation

If the installation replaces a GMA340, no changes are necessary as long as the existing installation meets
the requirements. All existing functions of the GMA340 as well as all of the new capabilities afforded by
the KMA 30 will become instantly available. Be advised, the KMA 30 does not support 3 VHF Coms,
however. The KMA 30 handles two COM transceivers and a full-duplex cellular/satellite telephone.
Added capabilities include, IntelliVox®, DuTel™ duplex telephone, improved music fidelity and Soft
Mute™ and Karaoke™ muting modes, improved and more flexible music distribution control, internal
recorder function, and additional unswitched audio inputs.
Installations where the external marker outputs are connected to a Sandel 3308 Navigation Display will
require additional loading resistors. Refer to the Sandel installation data for more information.
2.4.3

Power

The KMA 30 is compatible with both 14 and 28 Volt DC systems. A five (5) Amp circuit breaker is re-
quired for all installations. Power and ground wires should be #22 connected to J2 Pins 8 and 9. Connect
airframe ground to J2 Pin 10 and 11 only. No dropping resistors are required.
2.4.4

Audio Panel interface

The KMA 30 is designed to interface with standard aircraft avionics, and presents a 510 receiver im-
pedance. For best results, a twisted-shielded cable is recommended from the avionics audio source to the
audio panel, with the shield grounded at the audio panel end.
Some avionics do not provide a separate audio low, and may introduce additional electrical noise into the
system. For best results, connect the audio low from the audio panel to the radio ground, using one con-
ductor of the twisted-shielded cable.
2.4.4.1 Speaker Load
The KMA 30 contains one speaker amplifier. Some units with internal speaker amplifiers, such as the
King Radio KX170-series, require a resistive load to prevent damage if their speaker amplifier is not used.
Connect the speaker output from the unit to the COM 2 Speaker load input on the KMA 30 (J1 27 WRT
28). The speaker load is 16 , 3W.
2.4.5

Transmit Interlock

Some communications transceivers use a transmit-interlock system. To fully utilize the Split Mode fea-
ture, this function must be disabled. Consult that manufacturer's installation manual.
200-890-5464
Bendix/King by Honeywell
KMA 30 Audio Panel and Intercom System
Installation and Operator's Manual
NOTE
Page 2-3 Rev. 1, Aug. 2012