04275385 is referenced by 316 patents and cites 7 patents.

An infrared personnel locator system using a periodic unique infrared identification code emitted from a battery-powered transmitter unit to identify the person carrying the transmitter unit to an overhead infrared receiver as the person enters the receiver's monitoring zone. The transmitter unit identification code together with the receiver identification code is communicated to a common control unit which displays the location of all of the transmitter units. For paging, the system provides alerting units which are selectively operated in the zone closest to the person being paged. Additionally, the system controls electronic locks for restricting access of users to certain locations or equipment. A telephone interface provides system access from the telephone network.

Title
Infrared personnel locator system
Application Number
6/65876
Publication Number
4275385
Application Date
August 13, 1979
Publication Date
June 23, 1981
Inventor
Lester L White
Indianapolis
IN, US
Agent
John A Caccuro
Assignee
Bell Telephone Laboratories Incorporated
NJ, US
IPC
G01S 9/56
G01J 1/00
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