I'm new to this field, and I found the below circuit online.
My intention is to use it to connect an Arduino to an 8-PIN Yaesu Rotator controller.
My questions are:
What are the parts that I've marked with blue rectangles and how would they appear on a breadboard?
What does "01" on capacitors that I've marked with yellow rectangles mean?
What do the symbols within the red rectangle represent?
What's the difference between a 2N2222 and 2N3904 transistor for this?