I'm not real sure about this, but here it goes... There is a program for Zshell called Ulterior Motive. With this, you can supposedly call ZS progs from w/in TI-BASIC progs or the TI85 home screen. I'm guessing that you could write a very simple program that simply calls up ZShell for you, but it's kinda pointless. Again, I'm not sure about this because I haven't used ZShell for a long time. It crashed my calc too many times.