+ { "command_response": "modem_configuration", "status": true}
+
+## C5 SD Card Status
+
+In order to check the status of the SD card, the following command is available:
+
+ { "command": "sd_mount_status"}
+
+Command response if the SD card is mounted correctly:
+
+ { "command_response": "sd_mount_status", "status": true}
+
+If the SD card is full, not enabled, or connected as a MSD, the device will respond with:
+
+ { "command_response": "sd_mount_status", "status": false}
+
+For more info see [c5_msd](https://github.com/openxc/vi-firmware/docs/advanced/msd.html).
+
+## C5 RTC Configuration
+
+To set the current time of the RTC, the following
+
+ { "command": "rtc_configuration", "unix_time": "1448551563"}
+
+The response is
+
+ { "command_response": "rtc_configuration", "status": true}
+
+For more info see [c5_rtc](https://github.com/openxc/vi-firmware/docs/advanced/rtc.html).
+
+## Extra Values
+
+Any of the following JSON objects may optionally include an `extras`
+field. The value may be any valid JSON object or array. The client libraries
+will do their best to parse this information into a generic format and pass it
+to your application. For example:
+
+ {"name": "steering_wheel_angle",
+ "value": 45,
+ "extras": {
+ "calibrated": false
+ }
+ }
+