The Altair 8800 is a microcomputer introduced in 1974 by Micro Instrumentation and Telemetry Systems (MITS) based on the Intel 8080 CPU. It was the first commercially successful personal computer. Interest in the Altair 8800 grew quickly after it was featured on the cover of the January 1975 issue of Popular Electronics. It was sold by mail order through advertisements in Popular Electronics, Radio-Electronics, and in other hobbyist magazines. The Altair 8800 had no built-in screen or video output, so it would have to be connected to a serial terminal or teletype to have any output. To connect it to a terminal, a serial interface card had to be installed. Alternatively, the Altair could be programmed using its front-panel switches.