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
Parallel Redundancy Protocol Parallel Redundancy Protocol Parallel Redundancy Protocol (PRP) is a network protocol standard for Ethernet that provides seamless failover against failure of any network component. This redundancy is invisible to the application. PRP nodes have two ports and are attached to two separated networks of similar topology. PRP can be implemented entirely in software, i.e. integrated in the network driver. Nodes with single attachment can be attached to one network only. This is in contrast to the companion standard HSR (IEC 62439-3 Clause 5), with which PRP shares the operating principle. PRP and HSR are independent of the application-protocol and can