User's Manual

UL-801 Installation Manual
Page 104
23-20-06 15 December 2011
(4) VDL Mode A - Ref: ARINC 618, DO-186B
VDL Mode A refers to the analog communication protocols exercised by the VHF
data radio (VDR) and supported by the UniLink to exchange ACARS messages with
any appropriately equipped ground system. This mode is equivalent to the plain old
ACARS (POA) function of historical CMUs.
(5) SatCom Communication Interface - Ref: ARINC 618, ARINC 619
Satellite-based communication is available to the UniLink through a digital interface
to an external satellite data unit (SDU). The SatCom interface provides an alternative
media to VHF for the transmission of ACARS messages supporting
FANS 1/A+, ACARS ATS, and AOC applications. Customer preferences usually
prioritize the use of SatCom communications lower than VHF communications
resulting in this function generally being used in Remote or Oceanic regions.
(6) ACARS - Ref: ARINC 618
The Aircraft Communications Addressing and Reporting System (ACARS) is a data
link protocol and message structure which allows communication of character-
oriented data between aircraft systems and ground communication service provider
systems.
(7) AOA - ACARS over AVLC Ref: ARINC 618
The AOA function transports ACARS messages using ACARS routing over VDL
Mode 2 Aviation VHF Link Control (AVLC) - the data link layer. AOA provides a
more efficient, digital exchange of air/ground ACARS messages than VDL Mode A.
(8) ACARS Air Traffic Services (for example, D-ATIS, PDC, OC) (TSO indirect) -
Ref: ARINC 622, ARINC 623
The ACARS ATS function is the exchange of text-based Air Traffic Services
information between the flight crew and ATS ground host processing systems. These
services include: Automatic Terminal Information Services (ATIS), Oceanic
Clearances (OC), Pre-Departure Clearances (PDC), Terminal Weather Information
for Pilots (TWIP), Pushback Clearances, and Expected Taxi Clearances.
(9) Airline Operations Control (AOC – for example, text weather, weight, and balance) -
Ref: ARINC 620
The AOC function is the exchange of text-based information between the flight
crew/aircraft systems and the operator’s AOC processing systems (for example,
dispatch, maintenance, or meteorological services) throughout all phases of flight
(pre-flight, enroute, and post flight). Data included in the messages can be drawn
from other aircraft systems (such as I/O concentrator buses or FMS units) or can be
entered by the flight crew via a control and display unit.
(10) Datalink Message Recording - Ref: ARINC 758, ARINC 619
Intending to improve safety, enhance efficiency, and increase air traffic capacity, the
trend of replacing voice communications between flight crews and air traffic control
(ATC) with datalink messages is becoming more prevalent. In order to aid in
potential incident/accident investigations, UniLink supports transmission of datalink
messaging records to an ARINC Characteristic 757 cockpit voice recorder (CVR).
Records presented to the CVR include messages exchanged between the UniLink and