FR664216A - Improvements to telephone systems - Google Patents

Improvements to telephone systems

Info

Publication number
FR664216A
FR664216A FR664216DA FR664216A FR 664216 A FR664216 A FR 664216A FR 664216D A FR664216D A FR 664216DA FR 664216 A FR664216 A FR 664216A
Authority
FR
France
Prior art keywords
telephone systems
telephone
systems
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
Other languages
French (fr)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Associated Telephone and Telegraph Co
Original Assignee
Associated Telephone and Telegraph Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Associated Telephone and Telegraph Co filed Critical Associated Telephone and Telegraph Co
Application granted granted Critical
Publication of FR664216A publication Critical patent/FR664216A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
FR664216D 1926-10-14 1927-10-12 Improvements to telephone systems Expired FR664216A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB25634/26A GB283643A (en) 1926-10-14 1926-10-14 Improvements in telephone systems

Publications (1)

Publication Number Publication Date
FR664216A true FR664216A (en) 1929-08-30

Family

ID=10230832

Family Applications (1)

Application Number Title Priority Date Filing Date
FR664216D Expired FR664216A (en) 1926-10-14 1927-10-12 Improvements to telephone systems

Country Status (3)

Country Link
US (1) US1745038A (en)
FR (1) FR664216A (en)
GB (1) GB283643A (en)

Also Published As

Publication number Publication date
GB283643A (en) 1928-01-16
US1745038A (en) 1930-01-28

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