KMA 28
Audio Amplifier/Intercom/Marker Beacon Receiver
5
KMA 28
KMA 28 Operation
Receive Audio Selectors
Receiver audio is selected through
two momentary and six latched, push-
button, backlit switches. Com 1 and
Com 2 are the momentary switches.
Because the rotary microphone
selector switch controls what transceiv-
er is being heard, the Com l and Com
2 push-buttons are of the momentary
type and do not remain in when select-
ed. This is also part of the "auto" func-
tion. You will always hear the audio
from the transceiver that is selected for
transmit by the rotary mic selector
switch.
The users can identify which
receivers are selected by noting which
of the green switch LEDs are illuminat-
ed. Push buttons labeled Nav 1, Nav 2,
DME, MKR (Marker), ADF, AUX (auxil-
iary), and SPR (Speaker) are "latched"
type switches. When one of these but-
tons is pressed, it will stay in the "in"
position. Press the switch again and it
be in the "out" position and remove that
receiver from the audio.
Key "click"
The KMA 28 is equipped with an
electronic "click" to provide additional
feedback for button operation. To acti-
vate the key click, push and hold
BOTH COM 1 and COM 2 receiver but-
tons for five seconds, and release.
Repeat to defeat the click.
Speaker Amplifier
The "SPR" in the push-button sec-
tion stands for speaker. This switch will
place all selected audio on the cockpit
speaker when this switch is selected.
Public Address (PA) Function
The KMA 28 has a public address
capability when an optional external PA
switch is installed. When this switch is
put into the PA position, the pilot's
microphone is placed on a speaker out-
put. The copilot can continue to use
the selected Com radio.
When this PA function is installed a
separate cabin speaker (rather than the
cockpit speaker) is usually utilized to
prevent feedback.
O M
I
V
O
L
PUSH
OFF/EMG
HI
LO
T/M
ISO
ALL
CREW
1
KMA 28 TSO
Com 1
Com 2
Nav 1
Nav 2
MKR
ICS
ADF
AUX
DME
SPR
Transmit
Swap
COM 1
COM 2
COM 3
COM 1/2
COM 2/1
TEL
Mic Selector
Swap Indicator
Transmit Indicator
Speaker Switch
Crew ICS/Music 1 Mute
Mounting Screw
Intercom Mode Select
Intercom Volume
Marker Beacon
Indicator Lamps
Marker Beacon Sensitivity &
Test/Mute Select
Receive Audio Selectors
Photocell
KMA 28 Control Function
