Heeheehee... This is soooo schoolyard.
All the cool kids pronounce it Ip-Sic, because, well... it's just not cool enough to spell it out. Not manly, not "operator", not "jaded experience" enough, you know? You don't want to be outside the gang, do you?
You also have to use aR-SiMP for RCMP, See-PaC for CPC, PLiCk for PLC, NaRA for the NRA, See-SSA for the CSSA, and See-GuN for CGN. 
Beyond the sarcasm, what I really mean is: Use Ip-Sic if you want: it's fine. Or spell it out if you want: you'll be clearly understood by everyone and if the crowd you're with is shallow enough to think making words from acronyms demonstrates some desirable attribute, you may want to find a better quality crowd.