the Snom 821 phone as a door video monitor


IP video intercom solutions

Loxone, Mobotix and other vendors now offer nice IP video door stations, which use VoIP (SIP) for the audio communication with door monitor stations or software clients.

This makes it possible to integrate the video intercom in your existing telecom infrastructure, and configure the door station like any other VoIP phone to call one or multiple VoIP phones, or call a GSM via your PBX or SIP gateway to the public telephone network.

The Mobotix T25 door station has the most extensive configuration options to allow almost any calling scenario you can think of. It can register as a client to an external SIP server, but also has a SIP server built in, allowing VoIP phones to register on the door station, and it supports video calls to SIP video phones.

The Loxone solution

The Loxone solution is much more limited since the door station can not initiate a call. The bell button triggers the software client.  Only devices that have a SIP stack, like the iPhone or Android phones (no tablets), can then setup a VoIP call to the door station. Hardware VoIP phones or other soft-phones can not be used, unless you can make them to initiate the call to the door station.

SIP video calls is not supported. The Loxone 'Door Controller' in the software client separately pulls jpeg images from the IP camera in the door station to provide video.

A better solution

At our business we had some requirements, more like a tradtional video intercom solution:

  • there should be 2 fixed and fully functional indoor stations: not a smartphone because it is mobile and not available when the user is not there; not a tablet at the wall because it does not support audio via SIP.
  • on a press on the bell button, both indoor stations should ring a distinctive ring tone, flash a light, and both immediately display the camera image, whithout having to answer the call: not a SIP video phone (like the Grandstream video phone wich is often proposed by Mobotix), since video is only provided after answering the call, and only 1 phone at a time can answer the call and display the video.
  • the indoor station must be able to open the door via a simple button press, even without answering the call
  • when the door is opened or when the call is answered, the indoor stations must be notified so the user knows when a call is answered by somebody else. 

Using a hardware VoIP phone has some additional advantages:

  • top quality audio
  • easy to set volumes
  • set call forwarding, e.g. to mobile phone
  • also use it as a desk phone for voice calls

Snom phones are currently the only VoIP phones that have all the features you need to build a solution for a SIP IP video door station:

  • full remote control over the phone via http requests
  • an XML browser that allows you to put pictures, texts and buttons on the phone's display
  • event based triggers and soft buttons that can trigger http requests
The Snom 821 has a 320x240 color display with a good quality to show camera images.

Our implementation

We have implemented this at our offices with a Mobotix T24 door station. A very similar solution is possible with the Loxone door station. 

When you purchase any of these products from our store, we will give you all the required configuration and help tailor that to your specific needs. Here is an idea how it works:

  • When someone presses the bell button
    • the T24 triggers a virtual input in Loxone, connected to the 'Door Controller' so we can use our Android phones as well to answer
    • the T24 calls the 2 Snoms simultaneously
  • The Snoms recognize the caller ID and
    • rings a distinctive ringtone and flash a light
    • request an XML page that defines the display:
      • an image from the camera
      • a line with buttons to change camera views and open the door
      • requests the same XML page again to get a fresh image from the camera
  • When someone presses the soft-button 'Open', the Snom triggers a virtual input in Loxone.
    • Loxone unlocks the door
      • Loxone sends a notification to the T24 to stop calling the Snoms
  • When someone answers via a Snom phone, the T24
    • stops calling other phones
    • notifies Loxone

The Snoms also allow you to display refreshing camera images as a background to the idle screen.

In our configuration, Loxone activates this when access is granted in the Access Controller, or when the door is open, so we can see who walks in and out the office.

Also notice that Loxone sends the room temperature to the respective Snom via a virtual output.

Next step is to create XML pages to control the heating, light and audio on the Snom's display.

Please note that the described system is not an 'easy' solution, because it depends on multiple components, i.e. the phone, the camera, the webserver, the network, each with their own configuration options, so we also can not write a simple installation guide. We however will help you set up your configuration to get a working system if you purchase the products from us.

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