The LaserWriter 16/600 PS and the Color LaserWriter 12/600 PS contain a bi-directional port that conforms to the recently released IEEE1284 standard. On the LaserWriter 16/600 PS this is a standard 25-pin parallel connector, but on the Color LaserWriter 12/600 PS this is a mini 25-pin connector.
In addition to its bi-directional mode, the parallel port can operate unidirectionally at reduced performance with the original Centronics parallel capabilities. One advantage of the bi-directional capability is that the printer can send printer status information back to the driver. The older Centronics standard parallel port was uni-directional which left it up to the user to monitor the printer for paper jams, paper out, and error conditions.
Using the bi-directional capabilities requires a specially wired parallel cable*, bi-directional parallel port on the CPU, and driver support. Although bi-directional parallel ports are included with an increasing number of high-end Windows based systems, there are still very few applications that utilize its features. This will probably change when Windows 95 is released.
Note: The Apple Bi-directional Parallel cable (M4235ZM/A) can be used with the Color LaserWriter 12/600 PS ONLY. Apple does not supply a bi-directional parallel cable for use with the LaserWriter 16/600 PS.