At Microsoft we called this "Red Time / Green Time". I had a card on my door that I could flip to either color. If the card was set to the red side people would

At Microsoft we called this "Red Time / Green Time". I had a card on my door that I could flip to either color. If the card was set to the red side people wouldn't interrupt me. If it was green it was fine to just walk in and start talking. We were required to have a certain amount of green time each day.