Hello guys,
I need to send signals from one Arduino to another one over 2wires (Vcc and Gnd). Also I need to power on first Arduino with same two wires.
Basically I need this Arduino Transmit data over power line - YouTube , Just I don't have any idea how to start with. Can you point me somewhere ? 
Thank you for any help
That movie shows a little brown upside-down circuit board. I think it is a mosfet or transistor. The second Arduino is powered via a diode and capacitor. That means that short drops in the power line is used to communicate.
The first one has the TX connected to the little circuit board and the second one has the RX connected.
I think normal Serial communication is used.
That circuit is not okay. The ATmega328P microcontroller can be damaged, because the diode is parallel with the internal protection diode. An extra resistor is needed to the RX pin of the second Arduino of 4k7 or 10k.
I'm not sure what the circuit is on the little brown circuit board. The TX signal is idle high. That means that high must result into 5V output for the second Arduino. Perhaps only a transistor is used, then the second Arduino gets 4.4V instead of 5.0V. Or a mosfet is used with an extra component, perhaps a transistor or a opto-coupler.
If you need to transmit the signal over very long cables, then it is possible to use some kind of radio signal over the cables. The RadioHead RadioHead: RadioHead Packet Radio library for embedded microprocessors has a RH_ASK mode which can be used.