Inventor
HENDERSON WALTER G
US13 patents
⚠️ This page may combine multiple inventors who share the name “HENDERSON WALTER G”. Patents are grouped by organization below to help distinguish them — per-person disambiguation is on the roadmap.
SUPRA PROD INC
11 patentsUS4727368AFeb 23, 1988
Electronic real estate lockbox system
SUPRA PROD INC266 citations99
US5602536AFeb 11, 1997
Data synchronization method for use with portable, microprocessor-based device
SUPRA PROD INC215 citations98
US5245652ASep 14, 1993
Secure entry system with acoustically coupled telephone interface
SUPRA PROD INC119 citations98
US4988987AJan 29, 1991
Keysafe system with timer/calendar features
SUPRA PROD INC143 citations97
US4914732AApr 3, 1990
Electronic key with interactive graphic user interface
SUPRA PROD INC267 citations97
US4766746AAug 30, 1988
Electronic real estate lockbox system
SUPRA PROD INC195 citations97
US4929880AMay 29, 1990
Electronic lock system with battery conservation features
SUPRA PROD INC65 citations95
US4887292ADec 12, 1989
Electronic lock system with improved data dissemination
SUPRA PROD INC108 citations95
US4947163AAug 7, 1990
Electronic security system with configurable key
SUPRA PROD INC94 citations93
US5046084ASep 3, 1991
Electronic real estate lockbox system with improved reporting capability
SUPRA PROD INC133 citations92
US4896246AJan 23, 1990
Electronic lock with energy conservation features
SUPRA PROD INC44 citations91