Welcome to the CD-RB20 Schematic page.
Dispite this being here for years, Pioneer seem never to hae bothered with it. Wish they'd tell all about the IP-BUS protocol.
Just right click and select save as the link below to get the image.
Warning! It is a little over 1Mb. Cant skimp on quality now.
CD-RB20 Schematic
nominous