COMPONENT MAINTENANCE MANUAL
AVIATION PRODUCTS
Model FA5000
Rev. 02 Page 53
July 21/17
Description and Operation
23–70
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the restrictions on the cover page of this document.
D. OMS Input
For the purpose of reporting the OMS input bus status in the Label 350 CVR Status
Word output, the CVR expects a valid OMS input “heartbeat” once per second on
the low speed OMS ARINC 429 input. The heartbeat is detected through the pres-
ence of a valid Label 227 input (including good parity) to the CVR. This Label 227 is
used only for heartbeat detection and is not otherwise processed by the CVR. If the
heartbeat is not detected during three consecutive seconds, the CVR will report the
CMS Bus (OMS input) status as “failed” in the Label 350 CVR Status Word output. If
the OMS input bus is not connected, then the associated Label 350 Status Word bit
12 can be ignored.
10. CVR DATALINK INPUT INTERFACE
The FA5000 CVR was developed specifically to satisfy recent requirements for Con-
troller Pilot DataLink Communications (CPDLC or “DataLink”) recording in addition to
the two hour audio recording capability. The DataLink recording function of the CVR
is generally compatible with ARINC 429, ARINC 757/A, ARINC 758, and ARINC
619. The interface is characterized by the following specifications:
F
Single, ARINC 429, High Speed, physical layer input interface (Pins 33/34)
F
Williamsburg Version 3, Bit
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Oriented Protocol for link layer interface
F
Includes support for ALOHA exchange (but not required)
F
Records all System Address Label (SAL) 157 and/or 156 full word inputs
F
Recording of all Label 270 and Label 276 DataLink status word inputs
F
Recording of all Label 350 CVR OMS status word outputs
F
32 Mbytes of crash survivable memory reserved for DataLink message recording
F
DataLink Valid Discrete input (Pin 56)
F
DataLink Fault Discrete output (Pin 31)
All Label 270, 276, 157, and 156 words input on the CVR DataLink interface will be
recorded to crash protected memory regardless of the parity (good or bad). Like-
wise, these inputs, if present, will be recorded regardless of the state of the DataLink
Valid discrete input (Pin 56).
A. Data Link Input and Encapsulation
It is generally recognized that the Williamsburg Version 3 CVR input will utilize only
Command frames containing the encapsulated DataLink message information.
These Command frames then include the ARINC 619 formatting which provides the
Network layer interface. However, the FA5000CVR records data at the link layer in-
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