Dimond ringA Dimond ring or Dimond ring translator was an early type of computer read-only memory, created in the early 1940s by T. L. Dimond at Bell Laboratories for Bell's #5 Crossbar Switch, a type of early telephone switch.StructureLarge-diameter magnetic ferrite toroidal rings with solenoid windings, through which are threaded writing and reading wires.UsesIt was used in the #5 Crossbar Switch and TXE telephone exchanges.