Invention Grant
- Patent Title: Telephone alarm system
- Patent Title (中): 电话报警系统
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Application No.: US52566431Application Date: 1931-03-27
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Publication No.: US1841197APublication Date: 1932-01-12
- Inventor: MASSONNEAU ROBERT F , ROBERTS THOMAS H
- Applicant: BELL TELEPHONE LABOR INC
- Assignee: Nokia Bell Labs
- Current Assignee: Nokia Bell Labs
- Priority: US52566431 1931-03-27
- Main IPC: H04M3/12
- IPC: H04M3/12
Information query
