Phase 1: Choose the wanted audio-video configuration

Define the requirements

The RS232 universal AV interface is able to control about all audio/video systems available on the market.
Example: A TELETASK client wants music in the kitchen, the living room and the bath room. He wants to be able to listen to the radio in the different rooms. In the living room and in the kitchen, he wants to listen to the DVD player and he also plans to buy a MP3 player with three streams (= up to three songs played at the same time).
The requirements of the user can be summarized in the table.
Based on the requirements of the user, the necessary audio components can be defined and brought into a configuration drawing. For the used example, the schematic drawing should be like in the figure above.

When you select the components which you want to integrate through IR with the domotics system, you need to take care about:

  • The frequency can be between 36 – 38 KHz (most common) or 455 KHz.
!!! The used audio components must support the so called 'discrete on/off codes'. A discrete ON code, switches the audio component to ON. When the component is already ON, when sending the discrete 'ON' code, the system stays in the ON status. A discrete OFF code, switches the component to the OFF status. When the system was already in the OFF status, it remains in that status.
VERY IMPORTANT: Not all brands support these 'discrete ON/OFF' codes and within a brand there are components which support these codes and other components which do not. Therefore always ask your supplier if the device can process the controllable infrared 'discrete ON- and OFF' codes. Also ask if these codes can be generated by the remote control, so you can learn them to the RS232/learnable IR interface which needs these codes for obvious reasons or if the HEX codes are available.

When you select the components which you want to integrate through RS232, take care about:

  • The serial communication of the devices should work on one of the following Baudrates = 9600 / 19200 / 38400 / 57600.
  • The interface is always working with no parity, no handshaking, 8 data bits and 1 stop bit.

When you select the components which you want to integrate through IP, take care about:

  • Socket based serial HEX or ASCII string
  • No high level protocols (http, xml, json,…)
Like for the IR codes there should also be support for 'discrete on/off commands' The protocol of the device should have a different string for ON and for OFF.
To implement feedback codes, it is important that the receive code of the selected device contains the information as well as what this information is about. E.g.: If you would request volume feedback, the receive code must say: volume 50 and not just 50.

In our example the configuration drawing leads to the next set of audio components:

3 separate power amplifiers with each having their own internal tuner
these amplifiers are used to be connected with the speakers in the living room, the kitchen and the bath room. The TELETASK RS232 universal AV interface will control the different sources and amplifiers. In every room it is possible to listen to any tuner frequency, independent from the other rooms.
Remark: Although the user asked to be able to listen to the radio, you can offer him an unlimited and independent radio choice. This solution is to be preferred, because most home audio amplifiers for background music applications are only a limited percentage more expensive with an included tuner. The final cost of this may even be less expensive when compared to three power amplifiers with one separate tuner. Nevertheless, you may not forget to provide the necessary antenna amplifier / splitter to provide the necessary tuner signal to the different tuner inputs of every amplifier/tuner unit. In this example case, you need an antenna amplifier/splitter with at least 3 antenna outputs.
1 x DVD player
This one is external and is connected to the audio signal inputs of both power amplifiers, to be able to listen in the different rooms to the DVD player source.
1 x RS232 MP3 player with 3 streams
This one is also an external audio source, to be connected to every power amplifier. These can contain a huge number of music tracks.

As soon as you have selected the necessary audio components, you can start setting up the configuration drawing.
It is absolutely necessary to take good care for the making of this drawing. This will become an important tool to obtain the final solution smoothly.
Optionally you can add the brand and type of the audio component to the drawing.
As soon as the audio configuration reaches its final version, half of the work is done.
Only with an excellent drawing in your hands, you can go for the next step.
This drawing is also necessary to guarantee the support of TELETASK support service.

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