A nice fellow here on the forum sent me a PM with a lot of documentation for the fanuc om serial communication. I read through it and in one of the docs I found that parameter 0002 bit 2 should be set to 0 when its used. The exact text was "When RS-232-C Interface is used, set "0" to this parameter." and this bit is shown as irrelevant in the documentation I used before. I set it to 0 and it was working instantly sending and receiving. Really appreciate help like this. I would never have come this far on the machine without any help.
Since I got that working I started testing memory limit. I used my tool change program and copied it over and over until I hit the limit. In my simple Gcode that was on line 728 and equivalent to 9.84KB. I forgot to check how many characters it was. It had 7 left it said but If I added any more it just throw out the memory full error.
So I started looking at my memory board. From what I can see the only RAM installed is the NEC D43256AC-12L. This is 32KB chips and I count 4 installed. This should give me a total of 128KB and with 20M memory counting as approx 10KB that leaves 119KB for parameters and PCM settings. Doesn't that sound much? Is it likely that I got chips for 80M installed (40KB) and that there is 88KB ish dedicated for parameters? Anyways, can I just buy these chips, install and increase the memory amount to 320M without any problems? I have a backup of all parameters.
Another thing I noticed. Most say that 80M is installed. If I take 320M-80M it's 240M of tape. I know that 20M=approx 10KB so that's 120KB of memory missing from 80 to 320M. One chip is 32KB and that adds up to 128KB. Looks like I got chips installed for 80M and a max possible amount of 320M with all chips installed. Does my reasoning make any sense?