While technically correct that 2009 is the 50th anniversary of a contract between the NFL and CBS TV, CBS had contracts with a few teams for broadcasting away games for several years.
[for other posts on Steelers see http://sportbehindthemike.blogspot.com/
My father, Joe Tucker, was a pioneer in broadcasting both radio and television of Pittsburgh Steelers' games. His initial telecast in 1951 was carried by DuMont from Comiskey Park in Chicago (Steelers vs. Chicago Cardinals). His work for CBS TV began in 1954. His last report was in 1981 as a guest on a radio broadcast.
[Video of last broadcast]
Reading through his notes in preparation for writing his biography (Screamer: The Forgotten Voice of the Pittsburgh Steelers) I was surprised that he stuck with television. While there was more money and prestige in the visual media, the changes in broadcasting style, forced by production people who had no experience in football, brought down the quality of what a listener would get from an announcer. Cardinal Rule 1 with Joe was to provide an oral picture of everything that was happening on the field. This rule conflicted with Cardinal Rule 1 of the production people: Describe what the viewer was seeing on his TV set. What this conflict meant was that description of what flankers were doing on offense and linebackers were doing on defense, was not provided.
On a punt, the camera's focus was first on the punter and then on the receiver. Clips (now known as blocks in the back) were called by referees. The fan had no notion of the alleged crime other than it was called. The announcer was told not to relate his own view either of the fact or the severity; there was no replay.
As CBS moved towards a League contract, the number and force of production people increased. Perhaps the most disconcerting was the institution in 1958 of "time out for a commercial." CBS producers wrote specific guidelines instructing officials when to interrupt the flow of the game. While such interruption was to be as neutral as possible, timing was left to sideline officials who (at that time) were hired by the home team.
Television coverage has evolved to the state of art it is today, but the early days were chaotic and conflicted for announcing. If you're like me, you ignore the announcers who are often in another world and either turn off the sound or pay it no mind. You time chores of 4 minutes so that they occur with commercial interruptions that last at least four minutes. Games that used to last 2.5 hours now stretch beyond three hours, but the game has become genuinely entertaining, especially in high definition on a big screen.