It was very strange, and the change began about 1999 or so. Lotsof people noticed it. The call-in change was supposedly to be "fair" during the election, but they never went back to the old way.
Also, I have called them and been SCREENED, which they didn't used to do, and told my call wasn't pertinent. So not only are the lines weighted, but the conservative calls are screened.
And it wasn't. For the lefties that run C-SPAN. Their agenda is to suppress the conservative viewpoint.
/john