This is most likely as close as I'll ever get to hear a real one, so I wanted to make it near as possible to the real thing. Phoenix sound with two chuff input terminals on the board. No software tricks here, 4 magnets on one rear wheel of each power brick that pass over a reed switch. BTW, another NiMH battery that came back to life after 10+ years on the shelf. I have no complaints. Enjoy.