What it means
A barrier has a motor, an arm, a controller and safety devices such as a loop detector or infrared beam that stops the arm closing on a vehicle. The controller opens the arm when it receives a signal, usually a dry contact (relay) from an access system. That access system can be a guard's push button, an RFID reader, or an ANPR camera that matches the plate against an allowed list.
How it applies in India
In Indian residential societies and campuses, gates handle cars, two-wheelers, delivery vehicles and visitors in the same lane, often at peak hours. Check the opening time of the arm, its duty cycle, and whether two-wheelers pass beside it. When you add ANPR to an existing barrier, confirm the controller accepts a relay input and that the barrier fails safe when power is lost. GateGuard reads the plate and controls the barrier directly.