The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 01, 1991
Filed:
Jul. 06, 1988
Jay C Box, Garland, TX (US);
Tandy Corporation, Fort Worth, TX (US);
Abstract
The invention provides means for detecting errors in the transmission of protocol data words between the handset station and base station of a cordless telephone set. Assuming the protocol data words are eight bits in length, a sixteen bit security code word is provided which consists of a high security byte and a low security byte. At the transmitting station (either the hand set or base), the protocol data byte is exclusive-ored with both the high security byte and the low security byte. The two resulting bytes are appended to the original protocol data byte to form a twenty-four bit error detection code. This error detection code is transmitted to the receiving station. The receiving station takes the unaltered protocol byte portion of the three byte word and exclusive-ors it with both of the other bytes of the received word. If there were no transmission errors, the sixteen bit security code should be generated by the exclusive-oring step. If the resulting sixteen bit word does not match the security code stored in the memory of the receiving station, then an error is indicated and the receiving station request a retransmission of the data.