777 AIRCRAFT MAINTENANCE MANUAL
PAS -PASSENGER ADDRESS FAILURE MESSAGE
EFFECTIVITY BEJ ALL 23-31-00
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D633W101-BEJ Jan 05/2002
PAS -NORMAL/ALTERNATE PAC SELECTION FUNCTIONAL DESCRIPTION
General
The PA/CI controller has two passenger address controllers (PACs): normal and alternate. Only one PAC operates at a time. Usually the normal PAC operates. If the normal PAC fails, the flight attendants select the alternate PAC from the attendant switch panel (ASP).
The cabin system management unit (CSMU) and the zone managent units (ZMUs) monitor the status of active PAC on the intersystem bus. If the active PAC fails, a pop-up window shows on the cabin system control panel (CSCP) and cabin area control panels (CACPs).
Operation
The PA NORM/ALT switch is an alternate action switch. It sends a discrete signal to the CSMU.
The CSMU controls the signal. During normal operation, the switch signal goes through a switch in the CSMU to the PA/CI controller. When you test or install software, the CSMU controls the signal to the PA/CI controller.
Normal PAC
With the switch in the normal position, an open signal goes to the PA/CI controller. This causes the PA/CI to use the normal PAC. The alternate PAC is off.
Alternate PAC
When you push the switch in, a ground signal goes to the PA/CI controller. Also, the LED in the switch comes on. A ground signal causes the PA/CI controller to use the alternate PAC. The normal PAC is off.
Training Information Point
Because only one PAC operates at a time, you can use the PA NORM/ALT switch to help isolate passenger address system problems. If the problem goes away when the other PAC is active, the problem is in the PA/CI controller.
EFFECTIVITY BEJ ALL 23-31-00
Page 46
D633W101-BEJ Sep 05/2002
PAS -NORMAL/ALTERNATE PAC SELECTION FUNCTIONAL DESCRIPTION
EFFECTIVITY BEJ ALL 23-31-00
Page 47
D633W101-BEJ Jan 05/2002
PAS -RECORDED ANNOUNCEMENT FUNCTIONAL DESCRIPTION
General
The prerecorded announcement machine (PRAM) sends boarding music and recorded announcements to the passenger address/cabin interphone (PA/CI) controller.
Control
Flight attendants select the desired announcement or boarding music on the in-flight entertainment system (IFE). The IFE sends the data to the PRAM. The data goes to the announcement microprocessor.
Announcements
The announcement microprocessor sends an announcement selection to the memory cards. They keep the announcements in digital format in solid state memory devices.
The selected announcement goes to the PA/CI controller. The announcement key also goes to the PA/CI controller. This tells the PA/CI controller the announcement input is active.
Emergency Announcement Operation
When there is a decompression of the passenger cabin, a digital discrete goes to the announcement microprocessor of the PRAM. The announcement microprocessor selects the emergency cabin decompression announcement. The central processing unit sends a logic one to S1. This sends the emergency cabin decompression announcement to the PA/CI controller at the set EMERG volume.
Boarding Music
The PRAM uses two memory cards to store boarding music selections. Boarding music from the memory card goes through the output control to the PA/CI controller. The music key also goes to the PA/CI controller. This tells the PA/CI controller the boarding music input is active.
Pause
When the PRAM gets a pause signal through the CSMU, it stops the announcement output. When the pause signal goes away, the announcement restarts.
EFFECTIVITY BEJ ALL 23-31-00
Page 48
D633W101-BEJ Sep 05/2002
PAS -RECORDED ANNOUNCEMENT FUNCTIONAL DESCRIPTION
EFFECTIVITY BEJ ALL 23-31-00
Page 49
D633W101-BEJ Jan 05/2002
PAS -PA/CI CONTROLLER FUNCTIONAL DESCRIPTION
General
The PA/CI controller has two passenger address controllers (PACs), normal and alternate. Only one PAC operates at a time.
The PAC receives all PAS audio inputs. It continuously selects the highest priority input and sends it to the passenger cabin.
Audio Inputs
All audio goes to an audio switch matrix in the PAC. Priority 2B inputs go to the cabin interphone controller (CIC) in the PA/CI controller. The CIC sends audio to the PAC.
The PAS can have as many as six passenger address (PA) areas. Priority 1, 2A, 3A, and 4 announcements go to all PA areas. These only have one audio input each. Priority 2B and 3B go to selectable PA areas.
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