Image: AT&T coaxial trunkline 1949

Description: 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.
Title: AT&T coaxial trunkline 1949
Credit: 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
Author: Robert Hertzberg
Permission: 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.
Usage Terms: Public domain
License: Public domain
Attribution Required?: No