If you're new to video conferencing and Internet Telephony, choosing the right equipment can be a little confusing. Here's some information that should clear things up and help you choose the right camera. On the back of your computer you'll have several ports for connecting external equipment. This type of port has a 25 pin connector which is commonly used to connect a printer to your computer. You may not have a free parallel port to plug the camera into.
Parallel ports are the slowest of the three choices.
Parallel ports are slow, and when using them with a PC video camera, you will probably experience choppy video and slow frame rates. A frame rate refers to how many frames of video per second your camera can transmit - the lower the frame rate, the choppier the video. When transmitting video through a 28.8k modem, you're not going to get a very high frame rate even with a fast camera, but you may want a faster frame rate for other things, like making videos and sending them in emails, or setting up a web camera. Some parallel port cameras have a parallel port pass-through cable which allows you to hook up a printer or other parallel port device to the same port. If you're PC was manufactured before 1997, then you probably don't have a USB port.