VT220 COMPOSE Key Question

Jerome Fine replies: I would appreciate some help with the COMPOSE key on a VT220 LK201 keyboard, more specifically what it can do with the VT220 and the details of how it can be done. My actual problem is when I run an old PDP-11 operating system (RT-11), one of the application keypad keys (the keypad zero key - "<ESC>Op") sends out the same characters as the <GOLD> key ("<ESC>OP") except that the last character is upper/lower case. While the SL: (Single Line Editor) is running and the TTLC$ bit is on in the JSW (Job Status Word), it is possible to distinguish between both keys, but when an application program runs which turns off the TTLC$ bit, both keys look the same to the SL: if type ahead is used while the application program is running. Is it possible to change the <GOLD> key to output a different sequence of characters, or more specifically, either change the last character to "I" or have the <GOLD> key produce "<ESC>[36~" so it in effect becomes F22. I would then make the ENTER key = F21, PF1= F22 (as I just said), PF2=F23, PF3=F24 and PF4=F25. Alternatively, I would consider any other solution - probably even modifying RT-11 so that after an SS3 ("<ESC>O" sequence), the third character is not modified if the TANSI$ bit is on (a bit reserved for TECO) which could be a new command: "SET TT: [NO]ANSI". Note that when using RT-11 under Ersatz-11 from John Wilson, it is almost trivial to modify the ENTER, PF1, PF2, PF3, PF4 keys. So even if the temporary solution is to make these changes to the characters generated by these 5 keys, at least under Ersatz-11 it will work very well. Probably, such changes could be controlled via a FLAGn variable so that they could easily be toggled on and off. Note that Any comments would be appreciated. Sincerely yours, Jerome Fine