此app是专供D开门app的认证住户使用的辅助app，只提供一个功能：“视频开门”，通过app看到门禁机外的访客和景象。
This app is a tool of the “D开门” access control system. The users is same as “D开门”app’s users.
This app has two functions:
1) one is “Open door”
此app是专供D开门app的认证住户使用的辅助app，只提供一个功能：“视频开门”，通过app看到门禁机外的访客和景象。
This app is a tool of the “D开门” access control system. The users is same as “D开门”app’s users.
This app has two functions:
1) one is “Open door”