Characteristics: One door station can support up to four hundred indoor phones Dual talking, surveillance, intercom and remote door unlocking ID card function are optional With RF card reader function, you can unlock the door by RF card 30 ring, 20 monitoring and 120 intercom Twelve kinds of chord rings are optional Handsfree indoor phone and remote door unlocking Isolation between each doors offer good auto-protection (optional) Several kinds of our indoor phones can be exchanging completely LED in the door station provides a clear picture even at night time Color or black/white display are available Color TFT screen, 3.5, 4, 5, 5.6 or 7-inch size are available Remote control for the indoor phones in convenience for setting indoor phones and stop or start the defense freely Supports touchpad TFT Flush-mounted design for the door station and surface-mounted design for indoor phones