OFFICE CALL
  1 - Make a call
  2 - Hang up a call
  3 - Transfer to a preset number
  4 - Tranfer
  5 - Conference
  6 - "Pick-up" a call
  7 - Control ringing volume
  8 - Send numbers by tones (DTMF)
  9 - Alternate a call between two targets
  10 - Callers' identification, number and name

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  An interface indicating other extentions' states is also available
  1 - Extension 237, ... 2 - Extention 238, ...
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  We can easily verify if the extention is occupied, we can call the extension, step in, etc...
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  Have you ever thought about the produtivity increase of such a solution?