The square pin of the security door cannot be connected with the handle.

Does the subject want to ask "what is the reason why the square pin and handle of the security door can't be connected?" The reason why the square pin of the security door cannot be connected with the handle is to prevent the door from being pried open and improve safety.

1. Prevent the door from being pried open: If the square pin is directly connected with the handle, you can pry the square pin open by exerting a certain force on the handle, thus opening the door lock and causing the door to be stolen. If the square pin is not connected with the handle, it needs to be unlocked with a special key or password, which can better prevent the door from being pried open.

2. Improve safety: The square pin of the security door is not connected with the handle, which can improve the safety of the door, thus protecting the safety of articles and personnel inside the door. If the square pin is connected with the handle, once the door is pried open, the goods and personnel inside the door will face security threats.