patent holders. In the late 1980s units began appearing in the marketplace that were digital in nature rendering the analog, unijunction, R/C timer design obsolete. The new digital delay box timers used decimal or binary coded decimal thumbwheel switches to set countdown timer values in digital logic. The thumbwheels also fed back a visual numerical value that the race car driver could use to help him calculate proper settings. A popular early digital unit of this type was designed and produced by Robert Furrow (B. F. Electronics of Weatherford, Oklahoma). Robert Furrow's delay box utilized a quartz crystal for timing accuracy and Transistor–transistor logic (TTL) integrated circuits. Furrow's digital delay box was a substantial improvement in accuracy and ergonomics but suffered in reliability. In the United States many B.F. Electronics delay timers were sold Nationwide. Shortly thereafter the first microprocessor based delay box timer was introduced by Richard Beutnagel (Thorn Microsystems in Rochester, NY). Richard Beutnagel's design also used a quartz crystal time base for accuracy but without the TTL glue logic. The Thorn Microsystems unit utilized a single chip microcomputer from Intel, a professionally fabricated double sided printed circuit board with plated through holes, large BCD thumbwheel switches, and rugged solid state bipolar output circuitry (no electromechanical relay). The Thorn Microsystems design reduced parts count to "one chip" and one power transistor substantially reduced PCB (printed circuit board) solder interconnections for a significant enhancement in reliability. The firmware embedded within the Intel microcontroller chip performed all the timing and control functions required of the delay box with quartz crystal digital accuracy. Many new TTL and CMOS glue logic designs continued appearing on the market for several more years. Names like Meziere, Terminator, K&R, ATI, Digital Delay (Ike Hamma), Biondo, Davis, D&D (Danny Duberry) and others figure prominently in the history of drag racing delay boxes. Some of the glue logic type designs had large LED (light emitting diode) readouts to display the timer setting, others featured attractive backlighted LCDs (liquid crystal displays), still others used thumbwheels of varying size and quality. All delay boxes on the market were quartz crystal accurate by the year 1990. Several years elapsed before other delay box designs appeared with embedded microprocessors. Today, virtually all drag race delay boxes are microprocessor based with intelligent, backlit LCD readouts. The most popular models feature internal crossover time computation (allowing a driver to pick a visual cue