Entertainment Systems: Description and Operation
DESCRIPTION1. OUTLINE OF AVC-LAN
a. What is AVC-LAN?
AVC-LAN is the abbreviation for Audio Visual Communication-Local Area Network. This is a unified standard co-developed by 6 audio manufacturers associated with Toyota Motor Corporation. The unified standard includes signals, such as audio, visual and signals for switch indication and communication.
b. Objectives
Recently developments in car audio systems have been rapid and functions have been changed drastically. The conventional system has been switched to the multi-media type such as a navigation system. At the same time, customers want to upgrade their audio systems. This is the factor that lies behind this standardization. The concrete objectives are explained.
1. When products by different manufacturers were combined together, malfunctions such as sound failure occurred. This problem can be solved by standardization of signals.
2. Various types of after market products are available.
3. Because of the (2), each manufacturer has been able to concentrate on developing products in their strongest field. This has enabled the development of inexpensive products.
4. In general, a new product developed by one particular manufacturer could not be used due to a lack of compatibility with other manufacturers' products. By developing this new standard, users can enjoy a range of compatible products from different manufacturers anytime they want.
HINT:
- When +B short or GND short is detected in AVC-LAN circuit, communication stops, and the audio system does not function normally.
- When audio system is not equipped with a navigation system, the audio head unit is the master unit. When the audio system is equipped with a navigation system, the radio receiver is the master unit.
- The master unit is equipped with a resistor (60 to 80 Ohms) for communication.
- The car audio system using AVC-LAN circuit has a diagnosis function.
- Each product has its own specified number called a physical address (three-digit number). Numbers are also allotted to each function within a product, which are called logical addresses (two-digit number).
2. COMMUNICATION SYSTEM
a. This system performs communication between components through the Main AVC-LAN and Sub AVC-LAN.
b. The multi-display controller sub-assy functions as a master unit, which performs communication between the multi-display controller sub-assy and television display assy, in the Sub AVC-LAN circuit.
HINT: Refer to "TOYOTA NAVIGATION SYSTEM" and "AUDIO SYSTEM" for the Main AVC-LAN circuit.
c. The multi-display controller sub-assy is equipped with a resistor (60 to 80 Ohms) for communication.
3. DIAGNOSIS FUNCTION
a. The multi-display controller sub-assy functions as a master unit in the Sub AVC-LAN circuit on this circuit. It identifies trouble in this circuit, and the identified information is displayed on the television display assy.