-
公开(公告)号：US2494704A
公开(公告)日：1950-01-17
申请号：US61398445
申请日：1945-09-01
Applicant: BELL TELEPHONE LABOR INC
Inventor： GUTHE OLOF D M , SHANN OSCAR A
IPC: H04R21/02
CPC classification number: H04R21/021
Search Results
1
records
(took 0.011 seconds)
筛选
AND
AND
过滤
NOT
NOT
Scan to Join
