ATARI: 400/800: ADCM
The ADCM/ACDM Systems is a Canadian company (that apparently could not decide on their acronym). They produced software for Bot Engineering's 300 baud "Pocket Modem" exclusively for the Atari home computer line during the 1980's.
Both the terminal software (which came packaged in a cartridge) and the disk based BBS were written by Julius Oklamcak.
I don't know how many copies of the BBS were sold, but I think the number was quite low. I know of only two for sure - one hosted the HBO (Hamilton Burlington Oakville) Atari Users Group, and the second a BBS called the Scran Locker that I ran for 3 or 4 years in the mid-eighties.
To test the BBS, boot the "ADCM BBS Program Disk" disk, type "BBS" and when it has finished loading, insert the "ADCM BBS Files Disk" and press RETURN.
To login, press the START button and login with Username: SYS and a blank password.