The AF-142 and AF-241 ParaHubs are an automatic data switch that supports first-come, first-served printing. It can meet the needs of four computers to detect the printer's work and transmit data to the printer. When one of the computers accesses the printer, the other computers can only send their print jobs after the current job is completed. The file transfer performance allows users to access other computers directly through the ParaHub without the need for cables. In addition, the AF142 can also be used as a 1-to-2 selector (one computer output to two printers), and two parallel devices can be connected on the LPT port.