Invention Grant
US2847508A Stage-by-stage all-relay telephone switching system using voice frequency control
失效
使用语音频率控制的逐级全中继电话交换系统
- Patent Title: Stage-by-stage all-relay telephone switching system using voice frequency control
- Patent Title (中): 使用语音频率控制的逐级全中继电话交换系统
-
Application No.: US40812054Application Date: 1954-02-04
-
Publication No.: US2847508APublication Date: 1958-08-12
- Inventor: HOLDEN WILLIAM H T , EDWARD VROOM
- Applicant: BELL TELEPHONE LABOR INC
- Assignee: Microlithics Corp
- Current Assignee: Microlithics Corp
- Priority: US40812054 1954-02-04
- Main IPC: H04Q3/00
- IPC: H04Q3/00
Information query
