System conditions

The MOST bus can be in one of the following conditions:

Sleep mode

In sleep mode there is no data traffic on the bus. All devices are in back-up mode and so reduce the necessary quiescent current to a minimum. All devices can be activated at any time by an optical start impulse from the system manager. The sleep mode can only be activated if all the control units signal their readiness for this mode (i.e. no more processing of data is necessary). Furthermore no requests from other systems over the Gateway may be pending. The sleep mode cannot be activated during active diagnostics.

Standby mode

In standby mode the bus is indeed active, however all the output media (e.g. display) are turned off. This mode is active at starting and during a follow-up phase. This mode can be activated by a MOST control unit or an external control unit (e.g. unlocking the vehicle door, incoming call) if the bus was previously in sleep mode.

Power-on mode

In power-on mode all the control units are completely activated and make all the functions available for the user. This mode is active if the bus was previously in standby-mode and a MOST control unit or another control unit requests activity over the Gateway.