PRIMUS
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1000 Integrated Avionics System
A28--1146--112--00
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II Radio System
C--6
Integrated Communication Unit
The integrated communication unit, also known as the COM unit, is
identical in concept to the integrated NAV unit. It contains internal
modules that interface through a cluster module to the radio system bus
for operation. The modules in the COM unit are the very high frequency
(VHF) communication transceiver and the air traffic control (ATC)
transponder. The traffic alert and collision avoidance system (TCAS) is
controlled by this unit.
Radio Management Unit (RMU)
The RMU is the central control unit for the radio system. It controls the
operating mode, frequencies, and codes within all the units of the radio
system. The RMU can switch operation from its primary radio system
to the cross--side system. The RMU is an electronic controller with a
color and flat--panel display. It is used to select functions by pushing a
line select key adjacent to the parameter to be controlled. Any
selectable parameter, such as a VOR station frequency, can be
changed by pushing the line key next to the parameter and then rotating
the dual concentric controller tuning knobs.
The RMU display is divided into five dedicated windows. Each window
groups the data associated with a particular function of the radio
system. The windows (COM, NAV, transponder, ATC/TCAS, and
ADF) each control of the frequency, code, and operating mode of the
associated function. The RMU has other display modes, called pages,
that perform additional features and functions to control the radio
system. A menu of the pages access these additional features and
functions. In addition to standard RMU functions, the RMU can also
display navigation and engine data.
Audio Panel
The audio panel receives digitized audio from the remote navigation
(NAV) and communication (COM) units through a high speed digital
audio bus from each side of the airplane. Each audio panel selects the
proper channels from the digital audio bus and reconstitutes
headphone and speaker signals. The system can individually select the
radio function the crew member wants to hear using the audio panel.
The audio panel also has inputs for intercom, crew annunciation, crew
communication, hot microphone, etc., and full time emergency warning
inputs from aircraft systems.
