Can I I2C wire two Arduinos with USB cables on both?

Using Arduino Networking, Protocols, and Devices
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If you supply one Arduino, you can just connect the other with GND and 5V pins (on both MCs) and you have power for both. This works if the second Arduino doesn't pull too much power (the RTC is absolutely no problem).

Sharing the 5V between them with USB cables connected to both? Could it be done? Is there some kind of protection as it has when you connect both USB and power supply?

To wich network? In the previous posts you haven't had any network equipment involved. And what does "slave" mean in this context?

I'm sorry, I didn't know how to name it, I meant the I2C "network"...

Unfortunately there doesn't seem to be any documentation about that shield. The library is fully compatible with the Leonardo, my guess is, the shield is too. At least I couldn't find any specification that would rule against that. Do you have a schematic of the shield (I couldn't find one)? The EasyVR module is completely compatible with the Arduino Leonardo. If the shield isn't done too badly it should be as well.

As I said on the original post for the EasyVR Shield problem: I changed the pins to 8/9 instead of 12/13 and while normal operation it works fine (with some few bugs). But Leonardo can't operate as a brigde between the Shield and the EasyVR Commander app (used to upload, voice commands to the module). Neither in PC mode (there are jumpers in the shield to choose which mode to use), used to upload soundtables, as it was expected, since the Arduino is held in reset just to interface the module thru the USB serial using the default pins (12/13).

The official answer to this question via email is that:

the leonardo has differences in the pinout.
Please check the following pages where the differences are.

http://arduino.cc/en/Guide/ArduinoLeonardo
Serial - Arduino Reference

You need to change the pins accordingly.

which didn't get me very far, since there are no explanations about the pin diferences, only that Leo uses Serial1 instead of Serial to connect... I already tried changing on the libs, but without any changes.

Thank you for your constant help!