Initiator selects a talker and talker selects listener.
  Uses same steps as sending data but with ATN and other control signals 
    it indicate data is device id. Once selected :

While talker not indicating end of transaction 
Do
  Talker indicates data invalid (new transaction).

  Talker waits for listeners to finish any current data processing

  Talker puts data on data lines.

  Listeners notice data and acknowledge data exists.
  
  When Talker sees listeners listening, it indicates new data is valid.

  Each listener indicates it has grabbed the data.
    Only targeted listener does anything with the data.
 
  When all listeners indicate data accepted, talker indicates data invalid and 
    process starts over for next byte of data.
  
  * Protocol delivers 1 byte at slowest device's response speed.
Done