Main functions: 1) One door station can support up to thirty-two indoor phones. Different door station panels are available. 2) LED in the door station provides a clear picture even in nighttime. 3) Network application is optional; you can connect other door stations. 4) When you use this door station in a network system, the intercom between management unit and door station is possible. 5) Remote door unlocking and 3 melody ring or Ding-Dong ring is available. 6) Several indoor phones are available. 7) With RF card reader function is optional, you can unlock the door by RF cards.