Direct cable connection to a standard serial cable) must be used to connect each of the two computers to communicate properly. Such connection uses PPP protocol. If the parallel ports are used, Windows supports standard or basic 4-bit cable (commonly known as LapLink cable), Enhanced Capabilities Port (ECP) cable, or Universal Cable Module (UCM) cable (which was known as DirectParallel cable by Parallel Technologies). Infrared communication ports, like the ones found on laptop computers (such as IrDA), can also be used. Connecting any two computers using USB requires a special proprietary bridge cable. A directly connected pin-to-pin USB type A cable does not
ATX in favor of the more modern Universal Serial Bus. Other legacy connectors that are slowly being phased out of modern ATX motherboards include 25-pin parallel ports and 9-pin RS-232 serial ports. In their place are onboard peripheral ports such as Ethernet, FireWire, eSATA, audio ports (both analog and S/PDIF), video (analog D-sub, DVI, HDMI, or DisplayPort), extra USB ports, and Wi-Fi. Several ATX-derived designs have been specified that use the same power supply, mountings and basic back panel arrangement, but set different standards for the size of the board and number of expansion slots. Standard ATX provides seven slots at