Number | Name | Date | Kind |
---|---|---|---|
852806 | Smith et al. | May 1907 | |
986952 | Soles | Mar 1911 | |
1172614 | Lavalley | Feb 1916 | |
1518751 | Owen | Dec 1924 |
Entry |
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Western Electric Technical Digest No. 60 Oct. 1980, pp. 23-24 Lock For, "Call Director.RTM.", Telephone Set, O. Wagner. |
Western Electric Technical Digest No. 32 Oct. 1973, p. 25, Security Key Lock, W. A. Kasyan. |