Under GB/T 19056 and national transport safety regulations, what is the function and legal operating requirement for the Satellite Positioning Driving Recorder (行驶记录仪 / 北斗车载终端) on heavy commercial trucks?

1. It records vehicle speed, continuous driving time, GPS location, and driver identity in real time, and must remain powered on and connected to the national dynamic supervision platform
2. It is an in-cab entertainment television that plays movies for the driver during long highway hauls
3. It automatically pays highway tolls by deducting funds directly from the driver's bank account
4. It is a backup camera that operates only when the truck is in reverse gear