Which TTWinCE emulation do I use?

The emulation you need to use will depend on your host and the software running on it. For example, if you are connecting to an IBM iSeries you would most likely use the IBM5250 emulation.

If you are connecting to a Unix system, there are a variety of terminals available. If you have an existing setup but you don't know what the terminal type is, enter env at the shell prompt. This should return, amongst other things, the TERM entry. This is the terminal type you are currently using.