>  imho, if a scope shows a clean symmetrical vaweform after the opto,
>there should be no problem. pay attention to the rise and fall times, they
>should be negligible vs. the used baud rate (~30 usec/bit -> edges should
>be 3 usec wide or narrower).


aha! I have taken my DMM back to the shop and demanded they fit the scope
button back on it :-)

Seriously, I cannot afford a full scope, has anybody got any recommendations
of a cheap PC based scope system ( I can see VIPS and PICO in a catalogue
here.... )


Regards
Catchy....