Honeywell KTR 2280A Installation Manual page 88

SYSTEM INSTALLATION MANUAL
KTR 2280A
optimize the CSMA protocol is included in the VDL Mode 2 channel access protocol
specification.
As in Mode A, the Mode 2 data link channel selection is controlled by the CMF through the same
high-speed ARINC 429 interface used to exchange downlink and uplink AOA or ATN
messages. The CMF also dynamically controls the switching between Mode A and Mode 2
operation subject to available coverage. Since the VDL Mode 2 data rate and modulation
scheme differ from those used in Mode A, separate VHF frequencies and ground-based VHF
equipment must be used to give POA and AOA/ATN service coverage. As a result, the
availability of high-speed AOA service depends on the availability of ground stations.
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15 May 2017
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