Mazda 2006 MX-5 Service Highlights page 487

Time Division Multiplex
• For information exchange between electrical modules in a conventional system, a wire connection was
necessary for each information signal. However, by sending the different signal at varying times over one
channel, it is possible to send a large amount of information via a small wiring harness.
• In the conventional, non-multiplex system, in order to control the illumination of the five bulbs, one switch and
one channel was necessary for each bulb. For bulbs B and C to illuminate, switches B and C must be ON and
electricity must flow through the channel. With the time multiplex system, this can be done through one
channel. The channel is comprised of five data signal transmitters which transmit either a "0" or "1" signal to
indicate whether a bulb turns ON or OFF. For example, to illuminate bulbs B and C, transmitters B and C
transmit a "1" and transmitters A, D, and E transmit a "0". When the receiver receives these signal, bulbs B and
C illuminate.
NON-MULTIPLEX SYSTEM
A
0
0
B 1
1
C
1
1
D
0
0
E 0
0
Vehicle CAN System
• By rearranging the multiple signal, common information between the CAN system-related modules is
transmitted and received through the multichannel.
• The signal transmitted by one CAN system-related module is sent through the multichannel to all the CAN
system-related modules, but only the concerned module (s) receives the signal and performs the appropriate
operation (ex. light illumination, fan operation).
CONVENTIONAL
SYSTEM
ELECTRICAL
MODULE
ELECTRICAL
MODULE
CONTROL SYSTEM
A
0
B
1
C
1
D
0
E
0
EACH SIGNAL IS TRANSMITTED
ONE BY ONE THROUGH THE
CHANNEL AS IT IS RECEIVED.
ELECTRICAL
MODULE
TIME DIVISION MULTIPLEX SYSTEM
DATA
E D C B A
0 0 1 1 0
A
0
B
1
0=OFF
C
1
1=ON
D
0
E
0
EACH SIGNAL IS OUTPUT ONE BY
ONE AS IT IS RECEIVED FROM THE
CHANNEL.
CAN SYSTEM
CAN SYSTEM-
RELATED
MODULE
CAN SYSTEM-
RELATED
MODULE
A
0
B
1
C
1
D
0
E
0
C3U0940S007
CAN SYSTEM-
RELATED
MODULE
A6A8111T006
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09–40