usb ports
USB (Universal Serial Bus) ports were developed to standardize the connection of peripheral devices. Devices connected to a USB port may not require a separate power supply. Also, a number of USB devices may be able to be connected in “daisy chain” fashion when the number of available ports is limited.
References: http://compnetworking.about.com/od/usbnetworking/p/usb-port.htm
http://computer.howstuffworks.com/usb.htm
References: http://compnetworking.about.com/od/usbnetworking/p/usb-port.htm
http://computer.howstuffworks.com/usb.htm