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:
Dec. 31, 1991
Filed:
Dec. 21, 1989
Hideo Takai, Kanagawa, JP;
Tohru Futami, Kanagawa, JP;
Abstract
An off-board diagnostic device (master station) communicates with a plurality of electronic control units (subordinate stations) applicable to a vehicle. An initializing command (INIT) is transmitted by the diagnostic device to all electronic control units via a communication circuit. The master station (diagnostic device), then, transmits a system call command to the communication circuit to select a particular electronic control unit to be communicated with the master station. The selected electronic control unit returns a first echoback signal to the master station to inform the master station of the receipt of the system call command. Then, the master station transmits a control command (parameter set command) to the selected control unit to perform a predetermined control operation for a controlled obejct (e.g., vehicular engine). The selected control unit returns a second echoback signal to the master station in response to the control command. The master station, then, successively transmits at least two information signals to the selected control unit, the information signals being related to the control command. The selected control unit returns third and fourth echoback signals in response to the information signals to inform the master station of the receipt of each information signal. At this time, bit contents of the third and fourth echoback signals are determined depending on whether the bit contents of the first and second echoback signals are respectively the same as or logically opposite to those of the system call and control commands.