Communications Flashcards
What is the Com system
The purpose of the communications (COM) system is to supply the equipment necessary for communication in an aircraft, between different aircraft, and between aircraft and ground stations. It includes components used for voice and data communications. The COM system includes the following systems:
What is audio integrating system
Audio Integrating System
The audio integrating system controls the audio functions of the communication and navigation radios, headphones, microphones, and loudspeakers.
What is radio management system
Radio Management System
The radio management system provides tuning, control and system select capabilities to the aircraft communication and navigation radios via two radio management units (RMUs) and/or two flight management system (FMS) control display units (CDUs)
What is VHF com system
VHF Communication System The very high frequency (VHF) communication system receives and transmits voice/data between different aircraft and between aircraft and ground stations. The VHF COM system is a remotecontrolled integrated COM radio system. It transmits and receives voice/data between 118.000 and 136.975 MHz. The VHF COM has selectable channel spacing of 8.33 kHz (2280 channels) or 25 kHz (760 channels)
What is HF system
HF Communication System
The high frequency (HF) communication system is a long-range two-way communication system, which operates in the HF band from 2.0000 to 29.9999 MHz. It has 280,000 discrete operating frequencies in 100-Hz steps. The system can supply simplex and half-duplex operations.
What is sella
SELCAL
System A single selective calling system (SELCAL) is installed. This ground-to-air calling system supplies an aural annunciation and an EICAS message when a preset four-letter code is received by one of the aircraft HF and VHF radios. The system can monitor three VHF and two HF radios at the same time. This removes the continuous monitoring of the communication frequencies by the flight crew.
Who decides where aerials go
The purchaser !!
How many ICU,s
3
Is radio bus connected to IAC,s
Yes
What is ARTU
Airborne radio telephone unit
Uses VHF2 antenna through duplexer
What do Audio panels do
Audio Panels
Figure A3 The audio panel has manual controls that include pushbuttons, switches, and knobs. Each control operates as follows:
Microphone Selection
The top row of switches under the label TRANSMIT connect the MIC audio and PTT to the selected radio or PA (passenger address) amplifier when pushed in. The received audio is automatically enabled at the same time. An illuminated bar on the switch indicates that the function is active. Only one transmit pushbutton can be engaged at a time.
What does emerg switch do on Audio Panel
EMER Switch
This switch is located in the upper right corner of the AP. When pushed in, it bypasses all internal electronic circuitry and connects the onside headset directly to the onside VHF COM unit, AP 1 and 3 to VHF COM 1 and AP 2 to VHF COM 2. This switch disables all other functions on the AP.
What is VHF3
In normal mode is data only
What is sidetone
ST Switch The ST (sidetone) switch is used to adjust the sidetone level on the speaker to prevent undesirable positive feedback into the transmitting microphone. The sidetone level is independent of the volume control. This switch is also used as a speaker ON/OFF switch. The speaker is OFF when the switch is latched (pushed in). The speaker audio cannot be disabled when the oxygen mask is selected. The aural warning audio from the IACs, TCAS and EGPWS audio also bypass the OFF position of the ST SPKR ON/OFF switch. The aural warning audio has a preset level in the APs that is not affected by the SPEAKER audio volume control.
What is the system interface
Inputs
The APs receive analog audio inputs from the following sources: • Aural warnings from the integrated avionics computers (IACs) 1 and 2, TCAS and EGPWS • Flight interphone and service interphone audio • MIC audio from the hand mics, boom mics, and mask mics • The onside VHF COM to be used when the EMER switch is pushed Each AP receives inputs on two digital audio buses (DABs). These signals originate in the onside and cross-side integrated communication units (ICUs) and integrated navigation unit (INU). The received audio from the HF systems is sent to their onside ICU to be digitized and put on the DABs. The received audio from the VHF COM 3 is sent to INU 1 to be digitized and put on DAB 1.
What are RMU controls
RMU Controls
Figure B2 Photosensor The photosensor detects ambient light and causes the display brightness to be automatically adjusted to compensate for varying levels of light. Transfer Key The transfer (flip flop) keys are the two top keys on each side of the display. When pushed, they interchange the active frequency (top line) and the preset frequency (second line) of the window. If both transfer keys are pushed at the same time, the RMU enters aircraft maintenance mode. Line Select Key The line select keys are the next five keys on each side of the RMU display. The first push of a line select key moves the yellow cursor to that data field. This electronically connects that data field to the tuning knobs so that field may be changed. The preset line select key, if held for 3 seconds, enables the direct tune mode for the COM and NAV.
what is POC
Power on count
What is VHF com system
INTRODUCTION
The VHF communication system is used for line of sight voice and data communication. It covers the frequency range of 118.000 to 136.975 MHz. with a selectable spacing of 8.33 kHz (2280 channels) or 25 kHz (760 channels). The VHF communication system includes two Honeywell model RCZ-833E and one RCZ-833 series integrated communication units (ICUs). The RCZ-833E ICUs contain a VHF COM transceiver module, an ATC transponder module and a cluster module and the RCZ-833 ICU contains a VHF COM transceiver module and a cluster module. The VHF COM radios are normally tuned from the RMUs. VHF COM emergency tuning is available from the flight management system control display units (FMS CDUs) via an ARINC 429 data bus. COMPONENTS Figure C1 The VHF communication system consists of the following components: • Integrated communication unit (ICU) 1 and 2, model RCZ-833E • Integrated communication unit (ICU) 3, model RCZ-833 • In-line filters • Antennas- VHF COM 1- Dual VHF COM 2/UHF- VHF COM 3
Does VHF com 3 have transponder
No,send to other coms to transmit
As there are only two DABs on the aircraft, VHF COM 3 sends analog audio to INU 1 to be converted to digital audio and placed on DAB 1. The MIC audio (analog) and the PTT signals are sent directly from the audio panels to the ICUs.
When DATA mode is selected for VHF COM 3, the RMU sends status information to the DATA LINK unit. VHF COM 3 receives ARINC 429 tuning information, DATA KEY (PTT) and ACARS DATA for transmission from the DATA LINK unit.
How does it transmit
What does inline filter do
In-Line Filters
There are in-line, low pass filters installed between the VHF COM transceivers and their antennas. This filter is installed to prevent interference to GPS and SATCOM systems.
What are basic and direct tuning
Direct Tuning
Figure C4 To direct tune the COM, press the line select key beside the preset COM frequency and hold for approximately 3 seconds. The cursor will move to the active frequency, allowing direct tuning of that frequency, and the preset window will blank. To exit from direct tuning, press the line select key beside the preset COM frequency window and hold until the preset frequency reappears. Any memory location displayed inside the cursor can be changed by tuning and storing a new frequency. When the new frequency is tuned, the identifier will change from MEMORY to TEMP. This frequency (121.70) may be stored in MEMORY-1 location by pressing the STO button.
What is MIC STK
MIC STK
When the microphone is stuck for over 2 minutes, a beep will sound in the audio system, and this message will appear until the mic button is released. 10 seconds after the MIC STK annunciation appears, the transmitter automatically turns off.
What is the HF
INTRODUCTION
The aircraft has dual high frequency (HF) communication (COM) systems. They provide amplitude modulated (AM) and single sideband (SSB) modes of operation for long distance air-toair and air-to-ground voice communications. The operating frequency of the HF system is from 2.0000 to 29.9999 MHz in 100-Hz increments. Transmit power is selectable up to 175 peak envelope power in SSB and up to 50 W average in AM mode. Communication range on HF frequencies is much greater but less reliable when compared to VHF and UHF frequencies. HF communication range varies substantially, depending on several factors such as frequency, season, time of day, atmospheric noise, and solar activity. Tuning for the HF COM system is normally done by the two radio management units (RMUs), and the FMS CDUs provide backup tuning.
