The Atari 850 Interface

        The Atari 850 interface was probably the single most useful peripheral Atari ever created for its computer systems.    Designed by Scott Scheiman, the Atari 850 gave the original Atari 400/800 and the last XL and XE systems their "Eyes & Ears" so to speak.    The Atari 850 interface provided 4 separate RS-232-C serials ports addressed as devices R1: to R4: and a single Centronics compatible printer port.    This allowed the Atari computers to use industry standard modems, terminal, teletypes and printers.    The serial interface ports were female DB-9 connections (the same as on the original Macintosh 128,512 and Plus) as opposed to the standard IBM male DB-9 serial port connectors which the entire PC industry adopted and is still in use to this day.    The Centronics printer port is a non-standard DB-15 female connector which only Atari used.    Almost all other computer systems adopted the PC standard female DB-25 connector.

Scott Scheiman recalls:

        "Atari was preparing to show the new 850 Interface at the CES (Consumer Electronics Show) and everyone realized we had nothing written to demonstrate the 850 capabilites.     So in 4 days I wrote a terminal program that would later become Telelink 1 and would be packaged with the 850 Interface. "


Atari 850 Technical Data

Atari 850 Driver Modification Listing

Source Code to 850 Firmware

    While the Atari 850 was the only interface Atari ever sold to the public, many other devices and variations of the Atari 850 were made or used the Atari 850 interface case to house other various products.   Even Atari's own service division used the Atari 850 cases to house its various (SALT) Stand ALone Test units.    Other outside companies and parties used the Atari 850 cases for many odd and unusual projects, click below to see these various 850's.