Audio Amplifier/Intercom/Marker Beacon Receiver
A six-station voice activated (VOX) intercom is included in the KMA 28. This system
has the advanced IntelliVox® circuitry that eliminates manual adjustments. The system
contains six separate VOX mic circuits, and only opens the microphone channel in use.
The intercom system incorporates pilot isolate and crew modes, two stereo (or mono de-
pending on unit) music inputs with "Soft Mute," and LED indicators for swap and trans-
mit indications. Intercom control is through front panel-mounted knob and 3 position
mode switch. A single volume controls intercom level for the pilot and copilot. Passenger
headphone volume is factory set, and adjusted in flight with headset-mounted volume
controls. Passenger volume control is further adjustable through screwdriver access in the
top of the unit. Intercom squelch is automatic.
A 3-light Marker Beacon receiver is integrated in the KMA 28. This provides the neces-
sary Marker Beacon lights and audio indications necessary for an Instrument Landing
System (ILS) approach.
APPROVAL BASIS -
The KMA 28 Audio Selector Panel is FAA approved under TSO C50c (Audio Amplifi-
ers) and TSO C35d (Marker Beacon Receivers). In addition, they are approved by the
Joint Airworthiness Authorities under JTSO C50C and JAR-TSO 2C35d. The TSO
holder and manufacturer is PS Engineering, Incorporated, Lenoir City Tenn., USA.
The KMA28 complies with relevant portions of EUROCAE RTCA MPS WG No. 7/70,
DO-143 and (Marker Beacon Receivers), ED-14C/DO-160C (Environmental Conditions
and Test Procedures for Airborne Equipment), ED12B/DO-178B (Software Considera-
tions for Airborne Equipment) and ED- 18/DO-214 (Audio Systems Characteristics and
Minimum Operational Performance Standards for Aircraft Audio Systems).
Operation is subject to the following conditions:
This device may not cause harmful interference.
This device must accept any interference received, including interference that may cause
Rev. 0, Sept. 2000