# National System (SN)

SN-[LN.N].1The National System (SN) mode depends on the National System in use.

The responsibility of the driver in SN mode is specific to each National System.

SN-[LN.N].2When the Acknowledgement for National System symbol (MO20, located in area C1) is displayed with a flashing frame, the driver shall acknowledge the SN mode according to non-harmonised rules.

MO20: Acknowledgement for National System

SN-[LN.N].3When the National System symbol (MO19, in level NTC, the location is not specified) is displayed, the driver shall apply non-harmonised rules.

MO19: National System

SN-[LN].1The following mode transitions can be triggered from SN mode:

1. NP mode. Transition triggered when the ETCS on-board is powered off as indicated in section OFF.PWR Power off the ETCS on-board (PWR)).
2. SB mode. Transition triggered when the desk is closed as indicated in section OFF.CLS Close the desk (CLS).
3. SH mode. Transition initiated either manually by the Driver (see section SH.MAN Manual entry into SH (MAN)) or automatically by an order from the Trackside (see section SH.AUT Automatic entry into SH (AUT)).
4. FS mode. Transition usually initiated by an order from the Trackside (see section FS.RUN Running in FS (RUN)). This transition also includes a transition to level 1 or 2 initiated either manually by the Driver (see section LTR.TRS.DRV Level transition initiated by driver (DRV)) or ordered by the Trackside (see section LTR.TRS Level transitions (TRS)).
5. LS mode. Transition automatically initiated by an order from the Trackside (see section LS.APP Approaching an LS area (APP)). This transition also includes a transition to level 1 or 2 ordered by the Trackside (see section LTR.TRS Level transitions (TRS)).
6. SR mode. Transition to level 1 or 2 while the Override function is active (see section OVR.RUL Rules to pass an EOA (RUL)). This transition also includes a transition to level 1 or 2 initiated either manually by the Driver (see section LTR.TRS.DRV Level transition initiated by driver (DRV)) or ordered by the Trackside (see section LTR.TRS Level transitions (TRS)).
7. OS mode. Transition automatically initiated by an order from the Trackside (see section see section OS.APP Approaching an OS area (APP)). This transition also includes a transition to level 1 or 2 ordered by the Trackside (see section LTR.TRS Level transitions (TRS)).
8. UN mode. Transition usually initiated by an order from the Trackside (see section UN - Unfitted (UN)). This transition also includes a transition to level 0 initiated either manually by the Driver (see section LTR.TRS.DRV Level transition initiated by driver (DRV)) or ordered by the Trackside (see section LTR.TRS Level transitions (TRS)).
9. TR mode. Transition automatically initiated by an order from the Trackside (see section see section TR - Trip / Post Trip (TR)).
10. SF mode. Automatic transition triggered in case of a fault (see section SF - System Failure (SF)).
11. IS mode. Transition triggered when the driver isolates the ETCS on-board equipment (see section IS.ENT Entering Isolation mode (ENT)).