How long after the Tower of Babel did God call Abraham?
Approximately 200 years passed from the Tower of Babel until God called Abraham, according to the timeline given. That period is described as another approximate 200 years, placing Abraham's call at the midpoint of the earlier timeline from Adam to Abraham.
Les explains the timeline: from Adam to the flood was approximately 600 years, then about 200 years from the flood to the Tower of Babel, and another approximate 200 years from the Tower of Babel to the call of Abraham. He notes that this call is at the midpoint. Before Abraham, God dealt with one race of people for the first 2000 years, with no organized worship, temple, or written law; it was based on conscience and blood sacrifice by faith. After Noah and his three sons, the human race began splitting into three races.