User's Manual

UL-801 Installation Manual
Page 30
23-20-06 15 December 2011
UniLink supports transmission of datalink message recordings to any ARINC Characteristic
757 CVR/CVFDR.
The following information is sent to the CVR/CVFDR as part of the recording process:
• Uplinks to the aircraft
• Downlinks from the aircraft
• The time the message is displayed to the crew
• The crew's response to the message
• UniLink status data
• Any peripheral data that is addressed to the CVR
Records sent to the CVR may contain the following information:
• The message priority (if any)
• The display status of the message
• Time stamps of the message
• Other information required to identify the message.
The following examples describe ways that UniLink processes such data.
Example 1: Uplink to the Crew (Weather Graphic Received)
In the event that an uplink intended for display to the crew is received (Weather Graphic),
UniLink transmits a record to the CVR/CVFDR. When UniLink receives the graphic uplink,
UniLink displays the graphic.
Example 2: Downlink from the Crew (Crew-Commanded Downlink)
In the event that the crew generates or commands a downlink (a command to send a
downlink is initiated by the crew from CDU/MCDU), UniLink transmits a record to the
CVR/CVFD or UniLink queues a downlink. UniLink transmits another record once the
message successfully sends or if a message fails to send.
S. Printers
UniLink supports an interface to an ARINC 740/744/744A or a RS-232 serial printer.
UniLink only supports one printer in a configuration. If both ARINC and RS-232 serial
printers are configured, UniLink only uses the ARINC 740/744/744A printer.
UniLink supports printing of text data only. The maximum file size supported by UniLink is
16 KB, including any header and footer. If a print file is larger than 16 KB, UniLink discards
the print file and sends a message to the Status log.
NOTE: The file size limit was derived to provide a design guideline for reserving
memory for print jobs. The maximum file size from an ACARS uplink is about 3
KB and the maximum Williamsburg file size supported by UniLink is 6,320
bytes.