The PlayStation Link Cable (SCPH-1040) is a peripheral cable for the PlayStation console. Utilizing the serial I/O port located on the back of most PlayStation models, it allows for two consoles to be connected in order to play compatible multiplayer games on separate consoles.
The cable is a 12-pin inline serial cable[1] that plugs directly into the back of the PlayStation console and was a fully supported Sony accessory for the market life of the console. Due to the lack of a serial port on its hardware, this cable is incompatible with the redesigned PSOne.
The main advantage to using the cable was that a split-screen wouldn't be necessary for multiplayer, increasing screen-size per player and potentially increasing game performance (as only one view has to be rendered by the console). However, the use of this cable requires two televisions, two PlayStations (with appropriate cables) and two copies of the game being played (with the exception of C&C: Red Alert and C&C: Retaliation, which required only one copy as the games come with two discs).