When Paul Reed Smith took his creation, the PRS solidbody Custom to NAMM the first time, the coverless humbucking pickups were wired to a 5-position rotary selector switch. This delivered the standard bridge and neck pickups in positions 10 and 6, while position 8 delivered both (just like the middle position on a 3-way toggle). However, to give guitarists more tonal options, position 9 was a power out-of-phase sound using both pickups, while position 7 split the coils to deliver a sound similar to a Strat in the “in-between” position combining the bridge and middle single-coil pickups.
Some players loved this, though it was difficult to equate old habits (toggle and blade switches) with a rotary switch that was numbered 1-10, but only positions 6-10 actually worked. Subsequent rotary switches accessed slightly different sounds, but the concept was the same. In 1994, with the introduction of the McCarty, PRS went to a 3-way toggle switch and also later made this “McCarty switching” (with push/pull coil-tap) an option on almost all models.