Nivells PIC cable 5V dc from radio - Can i skip resistor and diode?

[gugges]

I´m testing to build a PIC serial cable for my dargonfly radio after the schedule



My radio gives 5v instead of 12v that is shown in the scheme, so I can´t use the 7805 due to the voltage drop, i guess I have the same problem over 1N4118.. can i skipp the diode or should i connect an alerantiv power source

the 47K ohm resistor, is it there to lower the voltage to the PIC? i that case I should remove that to.. leaving only the PIC! the signal source is also 5v from the radio...

Thanks in advance

[phildc]