Garmin G3X - Page 50

190-01115-01 G3X™/G3X Touch™ Avionics Installation Manual
Rev. AV Page 2-26
2.3.1.3.3 CAN Bus Termination
At each of the two extreme ends of the CAN bus backbone, a 120 Ω resistor is installed to terminate the
bus. In the G3X system, separate resistors are not required. Instead, termination resistors are provided
either within the LRUs themselves, or using termination adapters that plug into an LRU’s CAN
connection.
• The GAD 29, GEA 24, GMU 11, GPS 20A, GSU 25, and G5 installation kits provide a 9-pin
termination adapter that provides termination when attached to the device’s main connector. The
termination adapter contains a 120 Ω resistor that is connected between pins 1 and 2 (Figure 2-10
).
• The GDU 37X, GDU 4XX, GAD 27, GHA 15, and GSU 73 contain a 120 Ω resistor inside the
unit that provides termination when the CAN LO pin is connected externally to the CAN TERM
pin (Figure 2-11
).
• The GMC 507, GSA 28, and GTR 20/200 contain a 120 Ω resistor inside the unit that provides
termination when the two CAN TERM pins are connected together (Figure 2-12
and Figure 2-13).
• The GI 260 and GMA 245 do not have provisions for CAN termination. The GI 260 cannot be
installed at the end of the CAN bus. The total amount of extra wire length the GI 260 adds to the
CAN HI and CAN LO wires should not exceed 0.4 meters (15 inches). The GMA 245 can use the
9 pin termination adapter (011-02887-00) for a termination solution, by installing the unit in-line
rather than directly to the LRU connector. See GMA 245 Installation Manual for further
information.
Figure 2-10 CAN Bus Termination (011-02887-00) for GAD 29, GEA 24, GMA 245, GMU 11,
GPS 20A, GSU 25, and G5
Figure 2-11 CAN Bus Termination for GAD 27, GDU 37X/4XX, GHA 15, and GSU 73
Figure 2-12 CAN Bus Termination for GSA 28
GARMIN CAN TERMINATOR
GAD 27 &
GAD 27 &
GDU 37X/45X/46X/47X
5X/46X/47XGDU 37X/4
P3701/
P3701/
P4X01
4X01P
P271
1P27
2
3
1
NOTE: JUMPER (BETWEEN PINS 3 & 4) REQUIRED
NOTE: JUMPER (BETWEEN PINS 3 & 4) REQUIRED
WHEN GSA 28 IS LOCATED AT END OF CAN BUS
WHEN GSA 28 IS LOCATED AT END OF CAN BUS
CAN_TERM_1 3
CAN_TERM_1 3
CAN_TERM_2 4
CAN_TERM_2 4
GSA 28 PITCH SERVO
GSA 28 PITCH SERVO