FireWire is becoming the primary method of connecting external storage and video devices to PC. Also called the IEEE-1394 standard, FireWire, like the USB, has its own symbol, and is a block connector slight taller than the USB. Firewire connectors' transfer data thru 2 connection types, the 1392a and 1394b. these connections come in 6 and 9 pin connector respectively, and may be interchangeable which each connector type being on opposite end of the cable. SCSI ribbons are multi-connection cables used for making additional hardware connectivity to the "server." There are many different types of SCSI ribbons and devices, and each ribbon cable having their own connector types. PS2 or Mini Din is PS/2 connectors are a more standard version of USBs and are color coded for use with your mouse and keyboard. The purple is used for the keyboard, the green is used for the mouse. While these connectors are interchangeable in fit only, the connectivity will not work if housed in the wrong.