A short introduction to… IP video intercom

Analog intercom systems support only two-way voice communication. An IP video intercom (also known as video door entry, video doorbell, or outdoor station) features a camera that allows the end user to receive a live video feed of the person seeking access to the building. This way, the identity of a visitor can be visually checked before he is allowed into the building.

Video intercom systems offer many advantages over the traditional voice-based systems:

  • the indoor stations feature a high resolution monitor and can store video calls on the built-in SD card
  • the existing TCP/IP network can be used – no additional wiring is required
  • multiple indoor station can be configure to ring simultaneously when the call is made
  • the call can be forwarded to the mobile application so you can allow access to the building wherever you are
  • live video feed from the outdoor station is available even when the call is not being made
  • some indoor stations support adding a various I/O devices, such as a smoke or CO2 detector

Video doorbell system components

Outdoor station
The outdoor station features a built-in video camera and is installed at the building’s entrance. It can have one or more physical call buttons or even a numeric keypad for a larger installations. The outdoor station is connected to the electric strike that releases the lock latch if the end user decides to let the visitor in. The outdoor station is usually powered by a 12V DC power supply or a PoE device.

Indoor station
The video call from the outdoor station is forwarded to the specific indoor station. Indoor stations usually feature a high resolution touch screen. They are connected to a local LAN or Wi-Fi network and can be powered by a 12V DC or a PoE device. Some indoor stations offer additional features such as alarm I/Os, live video feed from surveillance cameras, video call recording on a built-in SD card, etc.

Electric strike
The strike is mounted on the door frame to allow the end user to open the door by pressing the open button on the indoor station.


How does a video doorbell systems works?
The following image shows a simple video doorbell system:

The outdoor station is mounted at the building’s entrance. Once the visitor presses the call button, the video call is forwarded to the specific indoor station. The indoor station of the end user rings indicating that a call is waiting to be answered. The end user receives a video feed of the outdoor’s station camera and can visually confirm who is at the door. The end user can decide whether to answer the call and allow the visitor inside the building.

Video doorbell system example installation
The following picture shows a simple video doorbell system:

As you can see from the image above, the system consists of a single outdoor station and three indoor stations. The video call from the outdoor station is forwarded to all three indoor stations that are configured to ring simultaneously. The outdoor station is connected to an electric strike which allows the end user to open the door to the visitor once the communication has been established. Notice how all system components are powered by a PoE switch, so the separate power supply is not even needed.




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