IntraSonic RETRO-DBB Door Bell Button Circuit Board

The Intrasonic RETRO-DBB door bell button circuit board allows a 2-wire door bell button to be connected to the RETRO intercom system.  This board is installed behind the master unit.  The 2-conductor wire from the door bell button in connected to the board.  A 3-wire adapter cord connects the board to the door speaker connector on the master.  This enables a standard door bell to ring a chime throughout the intercom system.