Kansas City standard - Definition and Overview

The Kansas City standard (abbreviated KCS) for storage of data on an ordinary compact audio cassette was also known as the BYTE standard or the CUTS (Processor Technology Computer Users' Tape Standard).

Developed in 1975, it uses asynchronous serial data, encoded using audio frequency-shift keying (AFSK) such that a '0' bit is represented as four cycles of a 1200 Hz sine wave, and a '1' bit as eight cycles of 2400 Hz. This gives a data rate of 300 bits per second.

Computers using the Kansas City standard included:

• Several S-100 based systems, such as the MITS Altair 8800
• PT SOL-20
• Ohio Scientific C1P/Superboard II
• Compukit UK101
• Acorn Atom
• Nascom (which also supported a 1200 bit/s variant)
• Motorola MEK D1 6800 microcomputer board
• SWTPC 6800 based computers

External links

• Sound sample of stored file (http://www.swtpc.com/mholley/AC30/memcon1.wav)
• SWTPC.com's article on the AC-30 cassette interface (http://www.swtpc.com/mholley/AC30/AC30_Index.htm)