Atari 800

This 800 version was called the 800D and was used by programmers for developing software. The system has a left side access panel that connects to a modified CPU board. There's 2 serial jacks and a bus expansion header that connect directly to the bus.

Several prototypes were modified to production specs and given to outside software developers to help with early software development.  These photos are of Engineering Trial #26 (as denoted by sticker on bottom) and was sent to Program Design, Inc. in Greenwich, CT.  PDI programmer Claus Buchholz created a notebook with photos noting the hardware differences.  As far as the case design differences, the name emblem is designed differently, with "ATARI" in outlined letters and "800" in a gradient gold.  Also, the controller jack numbers aren't molded in the shell but instead printed in a sticker.