Security system and method for electronic apparatus, particularly car radios or similar automotive audio equipment

US4720700A · kind A · utility

Assignee

• Blaupunkt-Werke GmbH · DE

Inventors

• Peter Seibold · Bad Salzdetfurth, DE
• Karl-Peter Strauss · Schifferstadt, DE

Key dates

• Filing date: Jan 21, 1986
• Grant date: Jan 19, 1988
• Expiry date: Jan 21, 2006

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60R2011/0096
• WIPO field: Control
• WIPO sector: Instruments

Abstract

Upon unauthorized removal of a car radio (2) from the chassis (C) of a car, a memory (5) which has a code stored therein is changed and inhibits operation of the car radio. The memory is retained in a predetermined memory state either by continuously receiving data inputs, for example from a potentiometer slider of a potentiometer (6), or data entered into an RAM energized only upon being properly connected in the vehicle. Alternatively, a user may enter a code, for example by operation of station selector buttons (4) of the car radio (2), and upon operating a set code switch (9), which code is destroyed upon removal of the radio, or upon failure to enter the correct code from time to time. The selected code can be encrypted by a preset encrypting memory chip, for example within the memory (5), and the encrypted code displayed, with only the manufacturer knowing the encrypting data, and releasing the encrypting data only to an authorized person, thereby permitting continued use of the radio by the authorized person even though the code word may have been forgotten.