Users Manual
ALL
EFFECTIVITY
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Page 5-52
22 Apr 2019
23-15-49
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ASPIRE-400
Table 5-15. Label 270: SDU to "ACARS" MU/CMU Status Word (Continued)
Bit Range Field Name (Discrete Format) Valid Values/Ranges
27
SATCOM Cockpit Voice
Communication 2
1 = Cockpit Voice Call Connected on 4-Wire2
0 = No Cockpit Voice Call Connected on 4-Wire2
28
Spare
N/A
29 SATCOM Data
1 = No Safety data link service available (see
Note)
0 = Safety data link services available
30-31
SSM (Note bits 30-31)
00 – Normal Operation
10 Functional Test
32
Parity
Odd
NOTE: Bit 29 is an extension of ARINC 741 definition.
(3) There is no support for message alert bits 15-16 in the Label 270 SDU to ACARS MU/
CMU Status Word.
(4) The ACD sets Label 270 Bit 14 SELCAL with the following timing:
(a) Set for a minimum of 4 seconds even if the call is answered or terminated within
4 seconds.
(b) Cleared for a minimum of 2 seconds before setting again.
(c) Continues to be set past the minimum of 4 seconds until the call is answered or
terminated.
(d) If a second call of higher priority occurs within 4 seconds of the first call being
answered, the Set state due to the first call must be a minimum of 4 seconds
followed by a 2 second clear, followed by a minimum 4 second Set for the
second call.
NOTE: The last bullet differs from ARINC 741 in that the Set state due to the
first call must be a minimum of 4 seconds followed by a 2 second
clear instead of 2 seconds followed by a 2 second clear.
(5) When any of the following bits get set (1b) due to the receipt of an incoming voice call:
(a) Bit 24 SATCOM Voice Alert 1
(b) Bit 25 SATCOM Voice Alert 2.
(6) The ACD sets the bit for a minimum of 4 seconds, even if the call is answered within 4
seconds of the bit being set.
(7) The ACD transmits the SDU to ACARS MU/CMU Join/Leave Word ARINC 429 Label 271
on the "Data to CMU 1 & 2" interface at a period of 1 second ± 100 ms with the bit fields
as follows:
DRAFT
3rd rvw Draft as of:
29 January, 2020