Reception, P and I Busses (2 Lead)

Reception, P And I Busses (2 Lead)







When a control module transmits, all the other control modules listen. The control modules listen by sensing the voltage difference between bus+ and bus -. A difference close to 0V is interpreted as a one and a difference close to 5V as a zero.

Appropriate combinations of ones and zeroes are transmitted according to a predetermined protocol so that all the control modules interpret the information in the same way. The message conveys what is being transmitted and the value thereof; e.g. "Coolant temperature 100�C", or "A/C ON".

Any electrical interference, e.g. from a relay, will cause the voltage on both leads to change in the same direction. The voltage difference is however unaffected and in this way the busses are very resistant to interference.