US2171542A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telegraph system
Assignee: AT&T Inc
•
Filing: 1937-08-17
•
Granted: 1939-09-05
•
Expires: 1957-08-17
Abstract
No abstract record available.
Inventors
- 👤 Cunningham Harold Jerome
- 👤 Douglass Lloyd Richmond
- 👤 Duncan James Archibald
- 👤 Walker Charles Robert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:43
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/16; H04J3/24; H04L; H04L5/00; H04L5/22
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1942-09-04 | 1943-03-06 | 1943-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1946-09-04 | 1947-03-06 | 1947-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1950-09-04 | 1951-03-06 | 1951-09-05 | $7700.00 | Window Closed / Lapsed |