Laplink

Laplink (sometimes styled LapLink) is a proprietary software that was developed by Mark Eppley and sold by Traveling Software.^[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. Traveling Software is now known as LapLink Software, Inc.,^[5] and their main software is now the PCmover.

LapLink for Windows screenshot

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. This so-called LapLink cable or null-parallel cable is capable of faster transfer rates than the traditional null modem serial cable. At the time, almost all PCs had a parallel printer port, but neither USB nor modern Ethernet was available.

A Laplink cable can be seen as a parallel equivalent to a serial null modem cable. Because of the higher bandwidth of the parallel port versus the serial port, a Laplink cable is able to transfer data more quickly.

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.^[6]

Wiring

The cable used two DB25 male connectors, and was wired as below:

D0	2	15	Error
D1	3	13	Select
D2	4	12	Paper Out
D3	5	10	ACK
D4	6	11	Busy
ACK	10	5	D3
Busy	11	6	D4
Paper Out	12	4	D2
Select	13	3	D1
Error	15	2	D0
Select In	17	19	GND
GND	18	18	GND
GND	19	17	Select In
GND	21	21	GND
GND	22	22	GND
GND	23	23	GND
GND	25	25	GND

See also

• Direct cable connection
• Ethernet cable
• Interlnk
• Parallel Line Internet Protocol (PLIP)
• Serial console