Hitachi service menu - 3 letter codes

Hi
I have been given a Hitachi TV model C32WF535N and have managed to get
into the service menu by pressing VOL+ and VOL- on the main TV for
more than 5 seconds and then also pressing the MENU button on the
remote until the service menu appears.
My question is that all options seem to be cryptic 3 letter codes. I
am trying to mess around with the HOT mode (hotel). I get 3 options
OPT (values 00..FE), VOL (volume level), PRG (values 0..99). What I
was trying to do was to get the TV to turn on to channel 6 at a nice
volume level. I set the values to OPT (00), VOL (nice level), PRG (6).
Every time I turn the TV on it is a lot quieter than what I set in
this service menu. After setting the values I had to go to the final
menu option and select E2X. I selected option E2S once and it seemed
to do a reset because when I turned the TV back on it wanted to rescan
the channels.
Does anyone have a list of what each of the 3 letter codes mean? I am
wary of messing with other settings until I know what they mean.
Thanks
Darren