Refined Printing Command Stream, also known as RPCS, is a vector-based[1] printing/duplicating control protocol, designed for communication between Microsoft Windows PC clients, and several lines of Ricoh copiers.
Drivers provided by Ricoh install the chosen copier to behave as a printer device.
The size-efficiency of the protocol is comparable to PCL6.
[1] Ricoh offers RPCS based drivers for Windows, Mac OS and to some extent for Linux.
Drivers for Linux are provided only on the Japanese website.