Well then, after all this time I finally have the necessary tools (at least I think I do) and knowledge to even attempt to connect to my Brocade FCX648-HPOE (picking up an old Cisco 887VA-K9 V2 (the old version) that was thrown out by a local medical center branch has helped in that regard).
Unfortunately, I cannot seem to be able to connect to it, no matter what I do (I was able to connect to the Cisco router without any issues, although I am still struggling to understand how to get it to acknowledge what is connected to it, and not just that something is connected).
I have tried using serial RS232 from my motherboard (started with an ASRock H97M, now with an Asus Z97 Pro Gamer), however have been unsuccessful in connecting to anything with the onboard serial controller (I tried both passthrough and crossover cables), so switched over to CH340G-based USB serial controllers (the USB to RJ-45 patch cable works well with the Cisco router, still need to test the USB to RS232 adapter in conjunction with the crossover cable), however even then I am unable to get any output from the console (I use Picocom, and I have verified that my settings are correct: 9600/N/N/8/1 with /dev/ttyUSB0, as dmesg and ls /dev/ report), whether I try using the front RS232 port pr the rear RJ-45 console port.
It appears as though the switch is working (despite it not serving DHCP) from the LEDs that remain on after initialization (PS1, PS2 and Stack ID 1), so I am really stumped here.