We didn’t have Box where I grew up (in the Bay Area) but according to Wikipedia,
@Wacky D is right.
At first, all of The Box's request lines used a large block of Miami telephone numbers and callers were only charged for a long distance call; however, in order to gain revenue, the network switched to the request line to a
1-900toll number, with callers being charged from $1.99 to $3.99 per call to make a request of up to three videos. The network was well known for being an "underground" outlet for music videos that were not shown or even banned on MTV, with up to 350 videos selectable at any given time in each of the 170 (by September 1992) different Box
affiliates throughout the United States.
Each affiliate had a unique playlist, usually customized to the local market, giving great exposure to more local and obscure groups.