Apple Power Macintosh 8500/120 Series - Manual (Page 61)

S-video connectors
The S-video connector is a round plug with several small metal pins. You can
plug this type of connector into your computer’s S-video input or output port.
IMPORTANT The S-video connector resembles other Macintosh connectors,
such as those for a printer, modem, mouse, or keyboard. Don’t confuse the
connectors; they’re not interchangeable.
Composite video connectors
Many video devices use composite video format instead of S-video. The
cables for these devices have RCA-type connectors (plugs).
Connect the RCA connectors to the appropriate composite video port (input
or output) on the A/V panel on the back of your computer.
RCA-type plug
S-video connector
49 Connecting Additional Equipment