User's Manual

ROCKWELL COLLINS
COMPONENT MAINTENANCE MANUAL with IPL
TDR-94, PART NO 622-9352
3
Comm B D ata Selector (BDS)
This 8 bit BDS field in UF number 1 contains the identity of the
ground-initiated Comm B register whose contents appear in the
MV field of the corresponding reply.
4
Designator Identification (DI)
The 3 bit DI field identifies the coding w ithin the special designator (SD) field in
UF numbers 4, 5, 20, and 21. The codes are defined as follows:
D
I DEFINITION
0 SD contains Interrogator Identification (IIS) information. IIS data is
basically the same as the II field except that it appears as a subfield in
multisite data protocol.
1 SD contains multisite information
2 SD contains extended squitter control information
3-6 (not assigned)
7 SD contains extended data readout requests
5
Interrogator Identification (II)
The 4 bit II field identifies the interrogator and appears in UF number 11 (Mode
S only all call).
6
Message, Comm A (MA)
The 56 bit M A field contains messages directed to the airplane during Comm A
interrogations (UF numbers 20 and 21).
7
Message, Comm C (MC)
The 80 bit MC field contains one of a sequence of segments transmitted to the
transponder in the extended length message (ELM) (112 bits) using
UF number 24.
8
Message, Comm U (MU)
The 56 bit MU field contains information used in air to air message exchanges
and is part of the long special surveillance interrogation using UF number 16.
This message field does not use the Comm A protocol.
9
Number of C Segment (NC)
The 4 bit NC field provides the number of a segment transmitted in an uplink
ELM message and is part of the Comm C interrogation using UF number 24.
1
0 Protocol (PC)
The 3 bit PC field contains operating commands to the transponder
and is part of surveillance and Comm-A interrogations using UF
numbers 4, 5, 20, and 21. The codes used in this field are as follows:
34-50-96
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May 18/06