A lot of the older CGA/EGA/Hercules etc monitors only used 9 pin connectors back then, it was only with S/VGA that they went up to 15<P>Be warned though, if the monitor is TTL type signals, trying ...

What Is the 9-Pin Outlet on My Computer For?. You can probably instantly recognize the USB, microphone, printer, speaker, SD card and power connectors found on your PC.