The 9915 was the rack-mountable, industrial-strength member of the 80 Series. The 9915 had the same features as the 83, excluding the screen and keyboard, but including the I/O ROM and Program Development ROM built in. The 9915 was the lowest cost computer in the 80 Series. It was designed to be a production-only machine. Normally, application development was done on an 85, and the program transferred to the 9915 via tape or EPROM. The 9915 was the only member of the 80 Series to include a cooling fan. The differences between the 9915A and 9915B (1984) are the same as the 85A and 85B.