What is a PC connector?
Some cameras, particularly some advanced amateur and most professional cameras, have a small round connector for hooking the camera up to external studio flash units as below. This is a PC connector. The PC stands for Prontor/Compur (two early camera shutter manufacturers) and not personal computer. PC connectors are not data connectors for computers or anything – they have nothing to do with USB or FireWire. All beginner EOS cameras lack PC connectors since they re mostly used in professional and semi-professional studio situations. If you really need one you can add a third party hotshoe to PC cord adapter to your camera. Most Canon Speedlite flash units do not have PC connectors. Those which lack them can be adapted via a hotshoe adapter, but generally do not work reliably when triggered by a PC cable. Even when they do work you lack all forms of automated metering, of course.
