LC PDS

From Mac Guides

LC PDS is an expansion slot first offered on the Macintosh LC computer introduced in 1990. PDS stands for (Processor Direct Slot) and is essentially all it was. As opposed to creating a system in which multiple cards could communicate with the processor, Apple took an inexpensive shortcut and simply made one slot and gave it direct access to the signal pins on the CPU.

In all cases previous to the LC PDS, PDS devices were processor specific, meaning PDS devices for a 68030 slot would not function in a 68020. The introduction of LC PDS was the truly universal implementation of Apple's proprietary PDS technology. A card that was made to work in an LC PDS slot would work in mostly all LC PDS equipped systems created afterward. As in every hardware device there are exceptions to this rule. One that is important to note is the internal orientation of the LC PDS slot would sometimes only accept cards of a certain size or shape (TV Tuners were commonly intended for a special LC PDS slot).