No DC, John, My layout is AC. I have a 9 Volt battery installed. I have lighted (AC) bulbs in several cars to pull juice.
The instructions state" the 10 volts AC is required to enable startup sounds... I think the ERR board will not work correctly in a Williams, without the ERR cruise commander as well.... This isn't the first 100 bucks I have wasted trying different things in the hobby. I am disappointed though that I just didn't go with the Williams sound board for 10 bucks less. Whether the sound is rated not as good as the ERR system, I could have lived with it........