I have a 3500s EFIS and a 3400s EM with map and XM for my RV-8. The instruction manual says I have to have an Ethernet hub from a 12V sourse with the dual screens. The manual recommends a Linksys 5-Port 10/100 Switch Model SE2500. The manual says this is a 12V unit. I looked this model number up and it is for house use. Where can I purchase the 12V unit? Thank You. Lyle