 DuMont struggled to get its programs aired in many parts of the country, in part due to technical limitations of network lines maintained by telephone company AT&T Corporation.During the 1940s and 1950s, television signals were sent between stations via coaxial cable and microwave links which were owned by AT&T.The service provider did not have enough circuits to provide signal relay service from the four networks to all of their affiliates at the same time, so AT&T allocated times when each network could offer live programs to its affiliates.