BE214-01
I10058
Radio Receiver Assembly Power Amplifier CD Auto Changer BE-126
- BODY ELECTRICALAUDIO SYSTEM
1730 Author: Date:
2001 AVALON   (RM808U)
AUDIO SYSTEM
DESCRIPTION
OUTLINE OF AVC-LAN
(a) What is AVC-LAN?
AVC-LAN  is the abbreviation, which stands for Audio Visual  Communication-Local  Area  Network.
This is a unified standard co-developed by 6 audio manufactures associated with Toyota Motor Corpo-
ration.
The Unified standard covers signals, such as audio signal, visual signal, signal for switch indication
and communication signal.
(b) Objectives
Recently the car audio system has been rapidly developed and functions have been changed drasti-
cally. The conventional system has been switched to the multi-media type such as a navigation sys-
tem. At the same time the level of customers needs to audio system has been upgraded. This lies be-
hind this standardization.
The concrete objectives are explained below.
(1) When products by different manufactures were combined together, there used to be a case that
malfunction occurred such as sound did not come out. This problem has been resolved by stan-
dardization  of signals.
(2) Various types of after market products have been able to add or replace freely.
(3) Because  of the above (2), each manufacture has become able to concentrate on developing
products  in their strongest field. This has enabled many types of products provided inexpensive-
ly.
(4) Conventionally, a new product developed by a manufacture could not be used due to a lack of
compatibility with other manufactures products. Because of this new standard, users can enjoy
compatible  products provided for them timely.
(c) The above descriptions are the objectives to introduce AVC-LAN.  By  this  standardization,  develop-
ment of new products will no longer cause systematic errors. Thus, this is very effective standard for
a product in the future.
HINT:
When +B short or GND short is detected in AVC-LAN  circuit,  communication  stops.  Accordingly  the
audio system does not function normally.
When audio system is not equipped with a navigation system, audio head unit is the master unit. (When
audio system is equipped with a navigation system, radio receiver is the master unit.)
The car audio system using AVC-LAN  circuit  has  a  diagnosis  function.
Each product has its own specified numbers called physical address. Numbers are also allotted to
each function in one product, which are called logical address.