Editing Atari ST (section)

=== Ports ===
[[File:Atari520ST Interface.jpg|thumb|Atari 520ST ports]]
[[File:Atari st mouse.jpg|thumb|Atari ST mouse (2000)]]

The ports on the 520ST remained largely unchanged over its history. 

====Standard====
* [[RS-232]]c serial port ([[D-subminiature|DB25]] male, operating as basic 9-conductor DTE)
* [[Centronics printer port]] ([[D-subminiature|DB25]] female, officially compliant only with the most basic unidirectional standard with a single, "Busy" input line; unofficially offering some bidirectional capabilities)
* [[Atari joystick port]]s ([[D-subminiature|DE-9]] male) for the mouse and game controllers
* 2 [[MIDI]] ports (5-pin [[DIN connector|DIN]], "IN" and "OUT")<ref name="midi">{{cite web |title=Atari ST Interfaces & Connectors |url=http://info-coach.fr/atari/hardware/interfaces.php |website=info-coach.fr |access-date=14 August 2018}}</ref>

Because of its [[parallel communication|bi-directional]] design, the Centronics printer port can be used for joystick input, and several games used available adaptors that used the printer socket, providing two additional 9-pin joystick ports.

==== ST-specific ====
* Monitor port (custom 13-pin [[DIN connector|DIN]], 12 of the pins in a rectangular pattern, carrying signals for both RGB and monochrome monitors, monophonic audio and, in later models, composite video)
* ACSI (similar to [[SCSI]]) DMA port (custom-sized 19-pin D-sub, for hard disks and laser printers, capable of up to 2&nbsp;MB/s with efficient programming)
* Floppy port (14-pin DIN, listed as operating at 250&nbsp;kbit/s)
* ST cartridge port (double-sided 40-contact edge connector socket, for 128&nbsp;KB [[ROM cartridge]]s)