20.4 INTERCOMMUNICATION SYSTEM Flashcards
How many MAPs are there?
Eleven
How many speakers and jack boxes are there?
Eleven
What does MMAP stand for?
Maintenance Mission Audio Panels
How many FDMCPs and FDACPs are there?
Three
What does FDIU stand for?
Flight Deck Interface Unit
What is the purpose of the FDIU?
Interface to VHF radios and navigation audio
The FDIU provides access to which radios?
VHF and one of the mission V/UFH radios (used as a UHF) for emergency operation
T/F The FDIU can mute speakers
The FDIU also provides speaker muting for the PA system so that when a crewmember keys the PA
system, PA speakers in the vicinity of that crewmember are muted so that there is no feedback
Where are the CSUs located?
Forward Comm Rack-E810
Briefly explain how the ICS works?
Analog voice enters the mic where it is digitized by the Crewmember Position Equipment (CPE) and sent via the T-1 Ethernet line to the CSU. From there it is sent to the Time-Division Multiplex (TDM) where it is made available to all the interfaces in the system.
Audio in the ICS is handled as digital information. Audio coming into the system from the crewmember microphone is digitized at the Crewmember Position Equipment (CPE). The PTT signal travels along with the audio information as a digital “flag.” The digitized audio is sent to the CSUs over a T-1 Ethernet line. The digitized voice is received by interface cards in the CSU and routed to a Time-Division Multiplex (TDM) bus that makes the digitized voice available to all the interfaces in the system. A fiber-optic digital network interconnects the two CSUs to make digitized audio generated in one of the CSUs available in the other CSU.
What are the functions of the CSUs?
Routes digitized voice for ICS communication
Crypto
Link 11
Sonobuoy command switching functionality
Located in Rack-E-810
What is the function of the MAP?
Primary Crewmember interface with ICS
Analog-to-digital and digital-to analog audio conversion
Where are the MAPs located?
Five MCWs Port and Starboard Observer Crew rest seats Mission Planning station Starboard sonobuoy rack Galley
What is the function of the junction box?
Primary interface between the Crewmember headsets and the ICS (through the MAP)
Also has speaker switch
Where is the speaker switch located?
On the junction box
Is there a functional difference between the OPERATOR and OBSERVER jacks on the junction box?
No
Both allow for communication via the MAP
T/F You can hear classified comms over the speaker?
False
Speaker switch. Allows user to listen to unclassified voice communications over external speaker. Volume is controlled by respective MAP location.
What is the function of the MMAP?
Tie headsets at the key fill panel (E-810 rack) to ALL CALL
Emergency intercom when aircraft is on battery power
The Mission Maintenance Audio Panel (MMAP) (Figure 20-28) enables crewmembers working at the keyfill panel (Forward Comm Rack-E810) to tie headsets into the ALL CALL net for communications at the position with either mission crewmembers or flight crewmembers. The MMAP is also a tie point for the emergency intercom that connects all users in the event the aircraft is operating on battery power (loss of all TRU power).
How many CSUs are there?
Two
