Jon,
[Link: hifi-remote.com] has a list of all the video discrete inputs and discrete power commands for Hitachi TV's. I am fairly certain that the discrete power and input commands are only recognized by a small subset of recent high end Hitachi RPTV's.
Some time ago, I posted a link to the official Hitachi commands at the JP1 Yahoo group in the links|Ir libraries section. IIRC, the exact models were defined that responded to the discrete power commands.
If you use your JP1 cable, it is very easy to do key moves. Take the EFC's listed in the link above and assign them to a key and use setup code 145.
If this doesn't work after you have done the keymoves, save the file in IR.exe, post it to jp-1 Yahoo group|files|diagnosis area and post a message to the Jp1 group describing the problem and one of us will look at what you did.
-Jon A
