I want to thank the people replying. I feel that I was not clear on my post (sorry).
I'm very concerned in the fact that the L14-30 has two 120 volt sources in the four prong twist plug. I know there are adapters out there to use on the four prong twist plug to the TT30 plug (standard 30amp motorhome plug).
My concern is, "will that adapter block the two 120 volts sources from hitting my coach system at once".
After additional research I have found that those adapter apparently do a good job of transferring the electricity from the L14-30 twist plug to the TT30 plug without danger of too much electricity.
Sorry if my post led anyone to believe I was considering the construct of some sort of wiring.