G900X/G950 Installation and Maintenance Manual – Pinouts
Page A-67
190-00719-00
Revision D
A.6.5 Configuration
Module Connections
Pin Name
Connector
Pin
I/O
CONFIG MODULE GROUND
P771
1
--
CONFIG MODULE DATA
P771
16 I/O
CONFIG MODULE POWER OUT
P771
17 Out
CONFIG MODULE CLOCK
P771
31
Out
A.6.6
AHRS System ID Strapping
Pin Name
Connector
Pin
I/O
AHRS SYSTEM ID PROGRAM* 1
P771
2
In
AHRS SYSTEM ID PROGRAM* 2
P771
3 In
By hard strapping the program pins to ground, the GRS 77 is assigned a System ID identified within the
transmitted ARINC 429 words. ID’s identify a GRS 77 as an All Call, #1, #2, or #3. For a single system,
the pins are left open (All Call).
The GRS 77 has an associated Source/Destination Identifier (SDI or System ID) that is coded into its
ARINC 429 output messages/labels. The System ID may be used to uniquely distinguish the source of
the GDC 74A ARINC 429 labels in a system with more than one GRS 77. The GRS 77 System ID can be
set to All Call, #1, #2, or #3 for such purposes.
A.6.7
GRS 77 System ID Strapping
By hard strapping the program pins listed in Section A.6.6 to ground or open, the GRS 77 is assigned a
System ID. The System ID is included in each transmitted ARINC 429 word. The System ID indicates
that there is only a single AHRS installed (All Call) or, if multiple units are installed, which AHRS the
data originates from (#1, #2 or #3). When a single GRS 77 is installed in the system, then the pins are
left open (All Call). Table A-3 shows strapping connections to achieve the desired system ID.
Table A-3. P771 Strapping to Achieve Desired System ID
System ID Number
ARINC System ID 1
Pin 2
ARINC System ID 2
Pin 3
All Call
Open
Open
#1 Ground
Open
#2 Open
Ground
#3 Ground
Ground
