.. _headlabel-refx-cmd-ssr:

SSR (Start-Stop Detection)
==========================

The `AT@SSR` command is used to detect the Start/Stop status of vehicle.
When the terminal detects that the vehicle enters Start, Stop or Long Stop status, it will generate and send the report carrying :ref:`Record 55H <headlabel-refx-record-55>` to the backend server.

.. code-block:: none

   Example:
   AT@SSR=gv500cna,,1,,5,60,120,0,,,012F$
   +ACK:SSR,123456789012345,8203,3,0,,012F,20210407101530,1234$
   AT@SSR?gv500cna,,0C37$
   +QRY:SSR,123456789012345,8203,3,0,1,1,,1,,5,60,120,0,,,0C37,20210407101530,1234$

.. tabularcolumns:: |p{2.2em}|p{14.2em}|p{5.8em}|p{12em}|p{4.8em}|

.. table::
   :width: 100%
   :widths: auto

   +-------+----------------------------+---------------+------------------------------------+--------------------+
   | Parts | Fields                     | Length (Byte) | Range/Format                       | Default            |
   +=======+============================+===============+====================================+====================+
   | Head  | Header                     | 3             | AT@                                | AT@                |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | Command Word               | 3             | SSR                                | SSR                |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | Leading Symbol             | 1             | =                                  | =                  |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | Password                   | 8-16          |                                    | gv500cna           |
   +-------+----------------------------+---------------+------------------------------------+--------------------+
   | Body  | Reserved                   | 0             |                                    |                    |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | `Mode`                     | 1             | 0,1                                | 0                  |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | Reserved                   | 0             |                                    |                    |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | `Start Speed`              | <=2           | 1-10 (km/h)                        | 5                  |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | `Time to Start`            | <=3           | 0-300 (seconds)                    | 60                 |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | `Time to Stop`             | <=4           | 0-1800 (seconds)                   | 120                |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | `Long Stop`                | <=5           | 0-43200 (minutes)                  | 0                  |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | Reserved                   | 0             |                                    |                    |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | Reserved                   | 0             |                                    |                    |
   +-------+----------------------------+---------------+------------------------------------+--------------------+
   | Tail  | Sequence Number            | 4             | 0000-FFFF ('0'-'9', 'A'-'F')       |                    |
   +       +----------------------------+---------------+------------------------------------+--------------------+
   |       | Tail                       | 1             | $                                  | $                  |
   +-------+----------------------------+---------------+------------------------------------+--------------------+

- `Mode`

  - **0** - Disable this function.

  - **1** - Enable this function.

- `Start Speed`

  Specify start speed threshold which to determine whether the vehicle is started or not.

  If the built-in motion sensor detects that the device is moving with ignition on, the device will start to check the speed from GNSS. If the speed value stays greater than 'Start Speed' for a period of time longer than 'Time to Start', the vehicle is considered to be in Start status.

  If the speed value stays lower than or equal with 'Start Speed' for a period of time longer than 'Time to Stop', the vehicle is considered to exit Start status (and in Stop status).

  **Note**: If GNSS fix is abnormal for more than 1 minute, the device will only use the built-in motion sensor to detect the Start/Stop status and does not check the speed.

- `Time to Start`

  If it is detected that the vehicle is moving with ignition on for the period of time specified by this parameter, the vehicle is considered to be in Start status.

- `Time to Stop`

  If the vehicle rests again and stays in that status for the period of time specified by this parameter after it enters into Start status, it is considered to exit Start status (and in Stop status).

- `Long Stop`

  Specify a time for Long Stop detection. In particular, if this parameter is set to 0, it means that the 'Long Stop detection' is disabled.

  After the vehicle enters into Stop status and stays in Stop state for the period of time specified by this parameter, it will be considered to enter into Long Stop status.