The CSP data frequencies are, well at least I last new, were integrated into the the trunked system Or are you referring to the MDTs? Those were a closely kept secret the last I knew when CSP upgraded their dispatch and MDTs software.
Data freq's would be the MDT stuff, but I am pretty sure they went to Verizon for the higher speed. There were lists around, due to some people running into them on their scanners and being hung up on them.
I was looking for the list to compare some channel plans.
Really nothing secret about them, just need to pay attention to the FCC data base.