For the Smart Control remote supplied with the Adapter, and the Xsight series of remotes, the code is 2555. This comes pre-programmed into the Smart Control unit supplied with the Adapter, and for the Xsight series this can be added via the ez-rc website (this can be found under DVD brand One For All).
For other OFA remotes, you can use code 0772 on the DVD key. As this is an older code, you may find that not every key reacts as you want, but this can be easily reprogrammed using key Magic. This is explained in another question in this FAQ section.
