More than a half-million cable T-V customers in Iowa will likely be writing out their monthly checks to a new company soon. A-T-and-T Broadband plans to sell its systems in Iowa and three other states to New York-based Mediacom Communications as part of a two-point-two billion-dollar deal. Debra Blume, a spokeswoman for A-T-and-T Broadband in Des Moines, says it’s part of a plan to cluster its systems in major metropolitan areas.A-T-and-T Broadband has 540-thousand customers in: Ames, Cedar Rapids, Clinton, Davenport, Des Moines, Dubuque, Fort Dodge, Iowa City, Mason City and Waterloo. Blume could not comment on the job security of the company’s one thousand Iowa employees. The deal also includes A-T-and-T Broadband properties in Missouri, Georgia and Illinois. The designated spokesperson for Mediacom has not returned Radio Iowa’s call.