A machine requiring periodic maintenance, such as a vending machine, is retrofitted to include an alert system for notifying a machine operator that the machine requires servicing. The alert system includes one or more sensors to detect default conditions, a voice recorder for storing one or more voice...http://www.google.com.au/patents/US20050008127?utm_source=gb-gplus-sharePatent US20050008127 - System for requesting service of a machine
