A method and apparatus for controlling DC balance in a digital communication system in which data frames (11) arc transmitted, wherein the data frames include a header portion ( 12) that is transmitted unscrambled and a pay toad portion ( 13) that is scrambled before transmission. The header portion includes a frame counter field ( 16) A value for the frame counter field is randomly generated (22) and an effect on the DC balance is estimated (23 ). It is then determined (24) whether the estimated effect on the DC balance meets defined requirements for DC balance, When the estimated effect does not meet the defined requirements for DC balance, a new random value for the frame counter field is generated and checked When the estimated effect meets the requirements, the randomly generated value is utilized (26) in the frame counter field in transmitted data frames.