Perhaps if you explain the question a bit better it might be possible to help you (both).
What kind of output are you looking at.
Assuming by CRO you mean a Cathode Ray Oscilliscope (kind of old fashioned term - (almost) no one makes the ones with actual tubes in any more.) :
You can look at signals on a scope - that's easy, if you have a modern scope it may be able to decode serial protocols.
It is possible to display text on a standard scope screen by making the right kind of signals (and this might be easier on one with a tube than on modern LCD types.)
So, please explain in a bit more detail what you are trying to do and suggestions may be forthcoming.
