Apple Macintosh Performa 577 - Manual (Page 10)

Specifications I/O Interfaces - 5
I/O Interfaces
Serial
Two RS-232/RS-422 serial ports; mini DIN-8 connectors
SCSI
One SCSI parallel port; DB-25 connector
Connects up to six external SCSI devices
Apple Desktop Bus
Two Apple Desktop Bus (ADB) ports; mini DIN-4 connectors
Maximum of three ADB devices recommended
Maximum current draw: 500 mA
(Mouse draws 10 mA, keyboard draws 25 mA)
Sound
Sound-output port capable of delivering stereo sound
Sound-input port for monaural sound input
Front headphone jack capable of delivering stereo sound