wrex began operation on october 1, 1953, as a primary affiliate of cbs. it shared abc with nbc affiliate wtvo, channel 17 (which signed on five months earlier), and also aired programming from the dumont television network. it was owned by greater rockford television, a group of local businessmen. the station's call letters were selected in honor of rex n. caster, the son of station president l.e. caster. rex caster was a first lieutenant in the united states army who was killed in france during world war ii.