what's channellized E1?

Hi friends, A very very basic question: What does "channellized E1" mean? What's its difference from a "normal" E1 connection? reply to my mail box, if you think such message is too basic posting on nanog, thanks. regards, Yu Ning -- ___________________________________________* Yu Ning ATM R&D Centre of BUPT (Beijing U. of Posts&Telecom) Beijing (ZIP:100876, MBox:147#), P.R.China Ideas ONLY reflect my own views,:-) ___________________________________________