ATTENTION ALL: Let me preface the following instructions for using KEYTIME by suggesting you familiarize yourself with RPN if you haven't already done so. It will help you maximize your experience with the HP 50G. All sensible people, upon being exposed to RPN, never go back.
So, the following instructions are for RPN users. I won't waste my time on you if you insist on not using RPN. You're cheating yourself in the end.
1.)
->KEYTIME and KEYTIME-> are both executable from the keyboard.
To be more specific: [ALPHA] [ALPHA] 5 0 0 -> K E Y T I M E [ENTER] will set the keytime to a value of 500.
[ALPHA] [ALPHA] K E Y T I M E -> [ENTER] will put the current keytime value on the stack.
2.)
If you must access these commands from CAT ( [Right-Shift] [SYMB] ), [ALPHA] [ALPHA] K will get you there a little faster.
3.)
Of course, you can put a program like << 500 ->KEYTIME >> in a variable named 'STARTUP', as outlined above by others, but you do not need to fool with FILES, APPS or any of that other junk. Variables (all variables, including ones containing programs and data) are accessed from the VAR menu. Just press [VAR] and you will see them.
4.)
You do not have to be in the VAR menu to key in a program. If you must have a program for the ->KEYTIME command, find the right-shifted function at the "plus" key (<<>>).
Press [Right-Shift] [+] [ALPHA] [ALPHA] 5 0 0 -> K E Y T I M E [ENTER] .
Then, [ALPHA] [ALPHA] S T A R T U P [ENTER] [STO].
You now have a program stored in a variable named 'STARTUP' that will set your keytime to 500. If you ever want to execute this program when you feel the urge, press [VAR] then [STARTUP].
5.)
Maybe you prefer some other value to 500. Use that value instead when you use ->KEYTIME or make a program that uses ->KEYTIME.
I apologize for seeming snippy and being overly verbose, but I become impatient with chasing commands via menus. You can do all kinds of stuff on the HP 50G or HP 48GX directly from the keyboard, if you know the name of the commands you're interested in. I find menus to be cumbersome and a last resort option. I don't mention the HP 49G, 49G+ or 48GII, because they are horrible pieces of junk better disposed of via hammer or acetylene torch.