Remote control system for selectively activating and inactivating equipment

US4633247A · kind A · utility

Assignee

• Blaupunkt-Werke GmbH · DE

Inventor

• Wilhelm Hegeler · Hildesheim, DE

Key dates

• Filing date: Aug 29, 1985
• Grant date: Dec 30, 1986
• Expiry date: Aug 29, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G08C19/28
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

Sixteen bit messages for selectively controlling receivers either to switch on an apparatus or to switch that apparatus off are transmitted on a format in which sixteen zeros are first transmitted, then a Willard sequence, then a control command, and then sixteen ones. The control command contains, in order of transmission, seven check bits, a control bit, seven address bits and a parity bit. The check bits are obtained by Nordstrom-Robinson coding from the eight data bits which consist of the seven address bits and a control bit, with cyclical rotation of the address bits but non-cyclical treatment of the control bit for deriving the seven check bits, with the result that, because the check bits and the control bit are received first, only three eight bit registers, each used twice first with the check bits as content and then with the address bits and the parity bit as content, are necessary for decoding at the receivers. The check bit comparison detects whether an on command or an off command is still possible and in one of those cases, treats the check bits as reversed in accord with the Nordstrom-Robinson coding, by the sign of the control bit.