Can Bus; Can Bus Architecture; Can Bus Backbone; Daisy-Chained Lrus On Backbone - Garmin G3X Touch Installation Manual

2.3.1.3 CAN Bus

The primary digital interface used to exchange data between LRUs in the G3X system is the Controller
Area Network, also known as the CAN bus. CAN was developed by Bosch GmbH in the 1980s, and its
specifications are currently governed by ISO 11898-2. CAN is widely used in aviation, automotive, and
industrial applications due to its simplicity and reliability.

2.3.1.3.1 CAN Bus Architecture

The electrical architecture of the CAN bus takes the form of a linear "backbone" consisting of a single
twisted wire pair with an LRU connected (terminated) at each end (Figure 2-6). The overall length of the
CAN bus from end to end should be 20 meters (66 feet) or less. At each of the two extreme ends of the
CAN bus, a 120 Ω resistor is installed to "terminate" the bus. In the G3X system, termination resistors are
provided either within the LRUs themselves, or via termination adapters that plug into an LRUs CAN
connection (see Section
CAN BUS BACKBONE: CONSISTS OF TWISTED, SHIELDED PAIR
WIRING CONNECTED TO CAN HI AND CAN LO OF EACH LRU, AND
PROPERLY TERMINATED LRUs ON BOTH ENDS OF BUS.
LRU
Multiple LRUs may be connected in a daisy-chain manner along the backbone of the CAN bus
(Figure 2-7).
LRU
190-01115-01
Rev. AC
2.3.1.3.3).
TERMINATION CONNECTIONS
Figure 2-5 CAN Bus Backbone
DAISY-CHAINED LRUs
LRU
TERMINATED BACKBONE LRUs
Figure 2-6 Daisy-chained LRUs on Backbone
G3X/G3X Touch Installation Manual - Installation Preparation
LRU
LRU
LRU
LRU
Page 2-17