Hi,
> i'm wrong or somethinmg like AuxHandler could be usefull?
Yes, the AUX-handler is just for this purpose. You could attache a serial terminal at the serial port of the Amiga and use the AUXhandler. This way you have a multiuser system :-)
The serial terminal can exexute any shell program.
It might be usefull for program testing by sending the debug output to the serial terminal.
Noster