Solution for wired communication between two arduinos - Two Wires

Hello, I am a beginner in the "INO" world, and I am developing a prototype that needs a solution for two arduinos to "talk". My scenario is: I have two Inos interconnected by a coaxial cable with a pair germinated. I need the speakers to talk, and, on the coaxial, traffic a video signal. Inos feeding is separated. I know it's possible, because I'm cloning an equipment that already uses this solution. Thank you in advance for the attention of the arduino.cc Family. Thanks

crschlosser: Hello, I am a beginner in the "INO" world, and I am developing a prototype that needs a solution for two arduinos to "talk". My scenario is: I have two Inos interconnected by a coaxial cable with a pair germinated. I need the speakers to talk, and, on the coaxial, traffic a video signal. Inos feeding is separated. I know it's possible, because I'm cloning an equipment that already uses this solution. Thank you in advance for the attention of the arduino.cc Family. Thanks

Perhaps a drawing showing the interconnections would be more informative.

Paul