What pointing devices can be connected to a CD-i player?
The Green Book defines that every CD-i system should be able to control the cursor on screen using an X/Y control device, including two action buttons. It is not specified in what way this should be taken care of, or how pointing device should be connected or interfaced to a player. However, Philips defined a connector type and interface format for pointing devices that is used on all Philips CD-i players, even the ones with a bundled Infra Red remote control (except the early CDI 180), and most CD-i players from other manufacturers (LG, Grundig, Memorex, DVS, etc.). This connection type is not part of the Green Book, but just a recommendation from Philips.
