What is a characteristic of all proximity door protective devices?

A defining characteristic of all proximity door protective devices is that they detect objects in the opening. These devices are designed to enhance safety by sensing when an obstruction is present in the door's path, thus preventing potential accidents or injuries during the door's operation. Unlike some devices that only focus on detecting items close to the door edge, proximity devices have a broader operational range and can identify obstructions further away from the door itself.

The goal of these protective devices is to ensure that doors do not close on people or objects, providing a key safety function in various applications, including elevators, automatic sliding doors, and similar systems. As a result, the characteristic that they detect objects within the opening is crucial for their intended purpose and effectiveness in preventing accidents.