A locking device that can be mounted into a rotating or swinging door is disclosed. The locking device can have a deadbolt. The locking device can detect the position of the deadbolt and/or whether the door is closed. The locking device can have a camera, microphone and speaker. The locking device can send images detected by the camera and audio detected by the microphones to a remote computer.

A locking device that can be mounted into a rotating or swinging door is disclosed. The locking device can have a deadbolt. The locking device can detect the position of the deadbolt and/or whether the door is closed. The locking device can have a camera, microphone and speaker. The locking device can send images detected by the camera and audio detected by the microphones to a remote computer.

A locking device that can be mounted into a rotating or swinging door is disclosed. The locking device can have a deadbolt. The locking device can detect the position of the deadbolt and/or whether the door is closed. The locking device can have a camera, microphone and speaker. The locking device can send images detected by the camera and audio detected by the microphones to a remote computer.

A locking device that can be mounted into a rotating or swinging door is disclosed. The locking device can have a deadbolt. The locking device can detect the position of the deadbolt and/or whether the door is closed. The locking device can have a camera, microphone and speaker. The locking device can send images detected by the camera and audio detected by the microphones to a remote computer.

A lock includes a housing in which a combination lock is received. The combination lock is unlocked when the combination unit of the combination lock is located at an unlocked position. The combination lock has a cam pin which is operated when the combination lock is unlocked and locked. A button is pushed to drive a cam which is located beside the combination lock. When the combination lock is locked, the cam pin is connected to the restriction hole to restrict the cam, and the latch is in its locked status. When the combination lock is unlocked, the cam pin is removed from the restriction hole. When the button is pushed, the cam is rotated to release the latch from the room of the housing. The combination of the combination lock can be changed by operating the operation bar when the combination lock is unlocked.