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
Serial digital interface application and interoperability. An 8-bit parallel digital interface is defined by ITU-R Rec. 601; this is obsolete (however, many clauses in the various standards accommodate the possibility of an 8-bit interface). In SD and ED applications, the serial data format is defined to 10 bits wide, whereas in HD applications, it is 20 bits wide, divided into two parallel 10-bit datastreams (known as Y and C). The SD datastream is arranged like this: whereas the HD datastreams are arranged like this: For all serial digital interfaces (excluding the obsolete composite encodings), the native color encoding is YCbCr format. The luminance