Topic summary
Voice messaging
Extracted from the Wikipedia article Voicemail.
IBM Audio Distribution System
ADS, marketed by IBM and briefly by AT&T Corporation, was well featured for voice messaging, the result of IBM's considerable human-factors research plus observation of operational use. Using a 1980s computer requiring air conditioning, it was expensive and physically large. With further development it grew to handle up to 3000 users, 100 hours of messages, multiple languages, message notification to a host computer, and 16 simultaneous users.