Atari 520 STM

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The second model in the ST range, the STM was virtually identical to the original ST, but with a built-in TV modulator (but still with an external floppy drive). The machine cost £400 when released.

The 520 ST featured same hardware basis and the same amount of memory as the 260 ST.

The main difference between them was the built-in ROM TOS operating system and GEM Graphics Interface. In fact, the Atari 520ST originally came with the OS on floppy as the OS was not completely finished. Very shortly afterward they came with the OS on 6 ROM chips (TOS 1.0).

It was first sold in Germany where it was met with great success. It was then released in the United States about six months later. Colour and monochrome version were available. Sadly, users of the colour version couldn't expect programs written for the monochrome version to work until someone wrote an emulator allowing the software written for the monochrome version to run on a colour monitor.

Atari was the first company to offer built-in MIDI ports. This made the computer very popular with musicians. One game even used the MIDI connectors (Midi Maze) to connect up to 16 computers together in a MIDI network.

The 520 ST+ offered 1 MB of RAM instead of 512 KB. As the main board was designed to provide space for only 512 KB of RAM (16 x 41256 type chips), the second 512 KB bank chips were soldered on top of the original chips.

Apparently, 1 Mb versions were sold as Atari 1040s in Australia.

The model 520 STM came with a built-in TV modulator allowing a direct connection with the TV-set.

Manufacturer Atari
Processor 68000
Speed (MHz) 8
RAM (KB) 512 RAM expandable to (KB) 1024
ROM (KB) 192
Sound 3 channels with noise
Keyboard type Typewriter-style
Number of keys 95 
Interfaces Cartridge port (40 way edge connector)
MIDI-in port (5 pin DIN)
MIDI-out port (5 pin DIN)
RF output
RGB/mono/composite monitor output (13 pin DIN)
external floppy connector (14 pin DIN)
DMA port / hard disc interface (19 pin D-type)
Centronics printer port (25 pin D-type)
RS232 interface (25 pin D-type)
mouse / joystick port (9 pin D-type)
joystick port (9 pin D-type)
Our model has a GI number of 10048 and a serial number of A1 68D 4009474 and was kindly donated by Dave Stevenson.

Manufacturer: Atari
Date: 12th September 1986

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Atari 520 STM Manuals:

Item Manufacturer Date
Atari ST Computer Owners Manual Atari 1986
Atari ST BASIC Sourcebook & Tutorial Atari 1986
Atari ST Engineering Hardware Specification & GemDOS BIOS Specification MTL Microtechnology Limited 7 Jan 1986
User Manual for the Atari ST Atari 15 Jun 1987
Atari ST BASIC Sourcebook and Tutorial (Revised Edition) Atari Nov 1988
AMOS 3D User Guide Mandarin Software 1990
AMOS Compiler User Guide Mandarin Software 1991

Magazines RELATED to Atari 520 STM in our Library

Item Manufacturer Date
Practical Computing - June 1988 Unknown
Practical Computing - September 1988 Unknown
MAG183 St Action Unknown
Computer Shopper April 1986 Apr 1986
Personal Computer World - September 1986 1 Sep 1986
Your Computer - November 1986 Nov 1986
Personal Computer World - January 1987 1 Jan 1987
Personal Computer World - February 1987 1 Feb 1987
Personal Computer World - June 1987 1 Jun 1987
Practical Computing - August 1987 Aug 1987
Personal Computer World - October 1987 1 Oct 1987
Personal Computer World - November 1987 Nov 1987
PC World Focus March 1989 Number 1 Personal Computer World Mar 1989
Personal Computer World - May 1989 1 May 1989
Personal Computer World - June 1989 1 Jun 1989
Personal Computer World - July 1989 Jul 1989
Personal Computer World - August 1989 1 Aug 1989
Personal Computer World - October 1989 Oct 1989
Personal Computer World - November 1989 1 Nov 1989
Personal Computer World - December 1989 1 Dec 1989
Personal Computer World - February 1990 1 Feb 1990
Personal Computer World - January 1995 Jan 1995
Edge - Issue 200 - April 2009 Future Publishing Apr 2009
Acorn User - November 1988 27 May 2009
Acorn User - February 1989 27 May 2009

Catalogues RELATED to Atari 520 STM in our Library

Item Manufacturer Date
Seven Disk - Atari ST Public Domain Software Catalogue - Autumn/Winter 1991 Seven Disk 1 Dec 1991

Other Systems Related To Atari 520 STM:

Item Manufacturer Date
Atari 800 with Programmer Kit Atari Inc 1st January 1979
Atari 400 with Aftermarket Keyboard Atari November 1979
Atari 800 Atari November 1979
Atari 400 Atari November 1979
Centipede Arcade Cabinet Atari 1980
Atari 1200XL Atari 1982
Atari 800XL Atari 1983
Atari 600XL Atari June 1983
Atari 520 STFM Atari 1985
Atari 65XE Atari 1985
Atari 520ST (boxed) + External hard drive + software Atari 1985
Atari 520 STM Atari 1st January 1985
Atari 1040 STE Atari 1986
Atari Mega ST 2 Atari 1987
Atari ST Mega 1040 Tower Power Atari 1988
Atari 1040STFM Atari 1989
Atari 1040STFM (David Arnold) Atari 1989
Atari 520 STE Atari 1989
Atari 1040STF Atari 1989
Atari Portfolio Atari 1989
Atari Stacy 2 Atari 9th December 1989
Atari Mega 4 Atari 1990
Atari TT030 Atari 1990
Atari Falcon Atari 1990
Atari Mega/STE Atari 1991

This exhibit has a reference ID of CH5769. Please quote this reference ID in any communication with the Centre for Computing History.


Atari 520 STM

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