Figure 1 Ports
The 9-pin socket supports an AppleTalk connection with the Apple Locking LocalTalk Connector Kit. The four position rotary mode switch must be set to the "AppleTalk" position in order to communicate with a Mac OS compatible computer. Serial communications to a DOS/Windows compatible computer can be achieved by selecting either 1200 or 9600 on the rotary switch.
The 25-pin socket will allow for RS-232c serial communication to a DOS compatible computer. It does not allow communication with a Mac OS compatible computer.
The LaserWriter and LaserWriter Plus do not support simultaneous communications.