Backlighting; Unswitched Inputs; Swap" Mode - Honeywell Bendix/King KMA 30 Manual

2.4.6

Backlighting

The KMA 30 has an automatic dimming of the pushbutton annunciation LEDs and marker lamps con-
trolled by a photocell. Control of the unit backlighting is through the aircraft avionics dimmer For 14 V
aircraft, connect J2 Pins 6 and 7 to the aircraft dimmer bus, and pin 5 to ground. For 28-volt systems,
connect pin 7 to the aircraft dimmer, and pins 5 and 6 to ground.
If an external dimmer control is not used, a constant back light illumination can be established for night-
time viewing. Pin 6 or 7 (depending on system voltage) must be tied to power (J2, pin 8 or 9) for the back
lighting system to work. The photocell mounted in the unit face will automatically adjust the intensity of
the push-button annunciator LEDs.
2.4.7

Unswitched inputs

J1, pins 31, 29 and J2 pin 15 are unswitched, unmuted (by transmitter keying), inputs # 1, 3 and 4, re-
spectively. These inputs are presented to the pilot and copilot regardless of the audio configuration, and
will always mute the entertainment inputs. These 510Ω inputs can be used for altimeter DH audio, GPS
waypoint audio, autopilot disconnect tones, or any other critical audio signal. Unswitched #1 is always
presented to the speaker, plus to the crew headphones, and is available to the pilot in fail-safe (off) mode.
Unswitched 3 and 4 inputs are always presented to the crew headphones and to the aircraft speaker.
Unswitched
Input
1
2
3
4
5 (jack)
Table 2-2 Unswitched input table
Unswitched #2, J1 pin 44 is unswitched is always connected to the Pilot's headphone. However, this
unswitched audio is only presented to the aircraft speaker when the SPR push button has been selected.
The audio low for unswitched #4 (J2, pin 15) should be connected to a convenient audio low. However,
this should NOT be connected to Music Low.
Unswitched #1 is presented to the pilot headphone in fail-safe (off) mode.
Inputs 1, 2 and 4 are fixed (1:1), and any audio level adjustments must be made at the input source.
Unswitched #3 has a variable adjustment control located on the bottom side of the unit. This control al-
lows you to adjust the volume level of that unswitched input. Refer to Adjustments section.
The front panel jack can be configured to act as a fifth unswitched input. When configured through the
front panel function switches (see operational section), the audio input to this jack will be presented to the
pilot and copilot headsets, and not muted.
The front-mounted utility jack is intended for portable equipment that is advisory in nature. It is NOT
INTENDED for use as a primary warning channel. Audio of importance MUST ALWAYS be hard-wired
into the unswitched inputs of the audio panel.
2.4.8

"Swap" Mode

When a momentary, normally open, push-button switch is connected between pin 20 on the J2 connector
and aircraft ground, the user can switch between Com 1 and 2 by depressing this switch without having to
touch the mic selector switch. This yoke-mounted switch eliminates the need to remove your hands from
200-890-5464
Bendix/King by Honeywell
KMA 30 Audio Panel and Intercom System
Installation and Operator's Manual
Hear in Hear in
Fail Safe Crew Headset
Yes Yes
No Yes
No Yes
No Yes
No Yes
NOTE
NOTE
Page 2-4
SPR button Gain
Select
No 1:1(fixed)
Yes 1:1(fixed)
No Adjustable
No 1:1(fixed)
No 1:1(fixed)
Rev. 1, Aug. 2012