Daniel L Henry

US Patent:

51462079, Sep 8, 1992

Filed:

Jul 1, 1991

Appl. No.:

7/723481

Inventors:

Daniel L. Henry - Boulder CO
Gregory A. Muir - Lyons CO
Joseph P. Desimone - Boulder CO

Assignee:

BI, Incorporated - Boulder CO

International Classification:

G08B 2100

US Classification:

340573

Abstract:

A field monitoring device (FMD) for use in an electronic house arrest monitoring (EHAM) system has an infrared (IR) communications port concealed in the back of its housing. A strain relief fixture for the power cord covers the IR port during normal FMD operation. This strain relief fixture is removable only with a special tool. The IR port includes two small holes. Inside one hole is an infrared receiver. Inside the other hole is an infrared transmitter. Data communications with the FMD is established by optically linking a matching infrared receiver included in a coupling head of an IR adapter with the infrared transmitter within the FMD; and by similarly optically linking a matching infrared transmitter with the infrared receiver within the FMD. The IR adapter interfaces with a conventional data terminal, such as a personal computer, which data terminal functions as an external programmer for the FMD. Only those who have possession of the external programmer, and who have the special tool and knowledge of the location of the infrared communications port, are able to establish a communications link with the FMD.