 During this era, American television programs were either broadcast live to local television stations via microwave relay and AT&T's coaxial cable service or were recorded on kinescope and delivered through the mail to local stations.The live broadcast method was expensive, but was preferred by executives at each of the four major U.S. television networks (ABC, NBC, CBS and DuMont); in 1954, DuMont alone spent $3 million on live television broadcasts.The major networks sent kinescopes to stations when live transmissions were not possible.