When the visitor visits, the resident is called at the entrance of the community through the wall machine. The corresponding resident can confirm the identity of the visit by voice intercom and video surveillance. After confirmation, the security is released and the visitor enters the park; when the visitor arrives at the door of the unit, the resident request is called again through the door machine. After unlocking, the household can confirm the remote unlocking of the unit door by pressing the unlock button; if necessary, the resident can install the second confirmation machine in front of the door. When the visitor arrives at the door of the household, the doorbell button is used to call the indoor unit. The resident can use the voice pair. After the final confirmation of video and video surveillance, the door is opened.