Do you remember?
At the NAB show held April 5 to April 8, 1964, Automatic Tape Control marketed the ATC 55 multiple cartridge handler. Built into a standard Cabtron rack cabinet, the unit could be installed as part of an existing automatic broadcasting system or it could be used as a cartridge library for live broadcasts.
The equipment featured a positive indexing direct current braking system, as well as gravity lock cartridge loading stops. Automatic electric dual relays were used throughout and the system was available in stereo.