If the scan mask cannot be read by the ATSU, the DEFAULT VHF SP LIST
 message is displayed in the MCDU scratchpad.
 If the VHF scan mask is unavailable, then the ATSU:

 -sends order to the FWCs to activate the display of the green left memo ACARS STBY or the DATALINK ATSU FAULT + ATSU INIT FAULT warning on the upper ECAM DU,
 -displays the ENTER VHF3 SCAN MASK message in the MCDU scratchpad.
 NOTE : Once the crew have entered the VHF3 scan mask in the VHF3 SCAN
____ SELECT page, the scan mask becomes available. Then, the ATSU resets the warning on the upper ECAM DU.
 **ON A/C 151-158, 201-209,
 Post SB 46-1009 For A/C 151-152,201-203,
 (4) Scan mask (Ref. Fig. 003B) The crew selects the VHF scan mask on the VHF3 SCAN MASK page. The VHF scan mask consists in an ordered list of service providers (SP) usable for VHF data communications.
R 1EFF : 106-149, 151-199, 201-299, 301-399, 1 46-24-00Page 52 1401-499, 1Aug 01/05 1 1 1CES 1 The scan mask is an ordered subset of the following list of authorized SPs proposed on the VHF3 SCAN MASK page:

 SITA Europe/Africa SITA USA SITA Pacific SITA Latin America ARINC Europe ARINC USA ARINC South America ARINC Korea AVICOM Japan AIR CANADA DEPV Brazil AEROTHAI Thailand ADCC China TEST AS (unavailable) TEST DA (unavailable)
 If the scan mask cannot be read by the ATSU, the DEFAULT VHF SP LIST
 message is displayed in the MCDU scratchpad.
 If the VHF scan mask is unavailable, then the ATSU:

 -sends order to the FWCs to activate the display of the green left memo ACARS STBY on the upper ECAM DU
 -displays the ENTER VHF3 SCAN MASK message in the MCDU scratchpad.
 NOTE : Once the crew have entered the VHF3 scan mask in the VHF3 SCAN
____ MASK page, the scan mask becomes available. Then, the ATSU resets the warning on the upper ECAM DU.
 **ON A/C 151-158, 201-209,
 B. ATSU sub-networks management The ATSU router handles VHF3 and SATCOM networks. Both networks can be active simultaneously in both uplink and downlink directions for different applications.

R **ON A/C 106-149, 151-156, 159-199, 201-299, 301-399, 401-499,
 Post SB 46-1013 For A/C 151-156,201-209,
 B. ATSU Sub-networks Management The ACARS Router is interfaced with ACARS sub-networks and manages simultaneously all air/ground subnetworks:
 -VHF through VDR3 in mode ACARS
 -SATCOM through SDU1 (optional)
 -HF through HFDR (optional).
R 1EFF : 106-149, 151-199, 201-299, 301-399, 1 46-24-00Page 53 1401-499, 1Aug 01/05 1 1 1CES 1 The VDR3 in mode ACARS is moreover used for voice mode communication between aircraft and airline. The ATSU router manages the voice/data mode changes for VDR3.

R **ON A/C 106-149, 151-199, 201-299, 301-399, 401-499,
 (1) VDR3 operation
 The VDR3 has two modes of operation:

 -
in VOICE mode, the interface linked to the Audio Management Unit (AMU) is activated: audio interface

 -
in DATA mode, the interface linked to the ATSU is activated:

 datalink interface. The VDR3 has two frequency control interfaces:
 -
a digital input port A linked to the ATSU,

 -
a digital input port B linked to the RMPs.
 The ATSU applies a command signal to the VDR3 and RMPs through the
 port select discrete:

 (a)
 When it is a ground signal The VDR3 takes into account its digital input port A and operates on the frequency transmitted by the ATSU

 (b)
 When it is in open circuit The VDR3 takes into account its digital input port B and operates on the frequency transmitted by the RMPs.

 NOTE : When the ATSU is not supplied or is faulty, the Voice/Data
____ select and port select discretes are in open circuit:
 -
the VDR3 operates in VOICE mode

 -
the frequency is controlled by the RMPs.

 (2) Voice/Data mode management (Ref. Fig. 010) The ATSU has direct control of the VDR3 switching between Voice and Data mode. The VDR3 default mode is Data mode. The switching can be initiated from:
 -any of the RMP by selecting ACARS in the RMP ACTIVE window for DATA mode or a frequency in the RMP ACTIVE window for Voice mode (activation of the remote port select discrete).
 NOTE : The switching command is initiated when the transfer
____ pushbutton switch located between the two displays is pressed.
 -any of the MCDU through the ATSU in the VHF3 VOICE DIRECTORY and VHF3 DATA MODE menus.
R 1EFF : 106-149, 151-199, 201-299, 301-399, 1 46-24-00Page 54 1401-499, 1Aug 01/05 1 1 1CES 1

 ATIMS - Voice/Data Mode Switching
 Figure 010
　
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