Laplink

[1] First available in 1983,[1] LapLink was used to synchronize, copy, or move, files between two PCs, in an era before local area networks, using the parallel port and a LapLink cable or serial port and a null modem cable[2][3][4] or USB and a USB ad hoc network cable.

LapLink typically shipped with a specialized cable, allowing two PCs computers to be linked together via the parallel port, establishing a direct cable connection.

At the time, almost all PCs had a parallel printer port, but neither USB nor modern Ethernet was available.

The Interlnk program on MS-DOS can also use the Laplink cable.

With the demise of parallel ports on PCs, Laplink no longer sells the traditional cable.