The DTJ-BBS was a program for the Commodore 64 written by Andrew Bernhardt. The first version was released in 1985, and sold for $35. There were forty DTJ systems before the software changed to freeware in 1989. DTJ-BBS was loosely based on the Citadel family of general discussion systems. Its primary function was a public message board, although it did support other features such as email and file transfers. Like Citadel, it used the metaphor of rooms to contain messages, and the system responded to many of the same menu commands. DTJ was written for speed and ease of use. No Commodore-specific features were supported. This was intended to make the system appealing to users of all computer types. The BBS was successful in this regard. DTJ systems tended to have a more diverse user base. Many users were surprised to find the software was not running on an IBM-PC but on a “toy” computer. Max Cottrell, editor of Commodore World's Sysop's Corner, ran the software and regularly mentioned it in his magazine articles. DTJ-BBS had a freeform text editor that did not use line numbers. The user was encouraged not to press RETURN or ENTER except at the end of paragraphs so that the message could word-wrap to the reader’s video width. The content of the text editor was non-volatile, meaning the user could exit the editor at any time and come back later to finish before saving it. Users with sufficient access could create rooms. The rooms were organized such that those with more message posting activity would contain more messages, and those with less activity would contain less. If a room did not get enough usage, it could delete itself automatically. DTJ-BBS also provided many features to make the sysop’s job easier. The sysop could send most Commodore DOS 2.6 commands to the drives, edit, move or remove messages, edit user accounts individually or in bulk, print audit trails for specific users, edit and copy files, and more. There was a sysop-configurable profanity checker that blanked out words in real-time, and a “twit detector” that detected hackers and other undesirable activity and adjusted the user’s status or performed other actions accordingly. DTJ handled speeds up to 2400 baud using the stock Commodore hardware, and up to 38,400 baud using Kent Sullivan's Swiftlink-232 serial cartridge. DTJ-BBS was written in compiled BASIC and assembly language. The source code was never released because it required a customized version of Skyles Electric Works’ Blitz! compiler, and a homebrew assembler. The final version of the software was the 950307 revision.