File:AT&T coaxial trunkline 1949.jpg
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English: Cross section of long distance AT&T coaxial cable trunkline used after World War 2 to carry telephone calls and television programs between cities. It consists of 8 coaxial subcables surrounding supporting steel strands. Each coax subcable could carry 500 telephone conversations or one television channel. This was installed January 16, 1949 between Philadelphia and Cleveland to link AT&T networks on East Coast with the Midwest. |
| Dato | |
| Kilde | Retrieved July 3, 2014 from Robert Hertzberg, "Coaxial cable joins east and midwest TV networks" in Tele-Tech magazine, Caldwell-Clements Inc., Bristol, Connecticut, Vol. 8, No. 2, February 1949, p. 19 on American Radio History website |
| Forfatter | Robert Hertzberg |
| Tilladelse (Genbrug af denne fil) |
This 1949 issue of Tele-Tech magazine would have the copyright renewed in 1977. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. Search of the Renewals for Periodicals for 1976, 1977, and 1978 show no renewal entries for Tele-Tech. Therefore the copyright was not renewed and it is in the public domain. |
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This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs.
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| Dato/tid | Miniaturebillede | Dimensioner | Bruger | Kommentar | |
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| nuværende | 2. maj 2021, 14:58 | | 657 × 664 (199 KB) | Materialscientist (diskussion | bidrag) | FFT |
| 28. mar. 2015, 19:32 |  | 657 × 664 (101 KB) | Chetvorno (diskussion | bidrag) | User created page with UploadWizard |
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