-
公开(公告)号：US2244004A
公开(公告)日：1941-06-03
申请号：US18994038
申请日：1938-02-11
Applicant: BELL TELEPHONE LABOR INC
Inventor： ERWIN EDSON L
IPC: H04Q3/00
CPC classification number: H04Q3/0004
Search Results
11
records
(took 0.012 seconds)
筛选
AND
AND
过滤
NOT
NOT
Scan to Join
