tri state

tri state

   <hardware> A feature of some {digital} electronic devices
   which allows a connector (pin) to either act as a normal
   output, driving a signal onto a line, or to be "tri stated" -
   set to a high-impedance ("high Z") condition.  This allows
   other outputs to drive signals onto the line.  Often the same
   connector also functions as an input when its output circuitry
   is tri stated.

   Tri-state outputs are typically used for the connection of
   several digital circuits to a shared {bus} onto which any one
   of them may output data for the others to input.

   (1996-07-26)