@guardian:
Good point… I've been staring at the port side of the box because of where it's mounted, so I forgot about those holes, so I could see possibly doing that.
Only thing is, if that is a serial port, wouldn't it show in dmesg? I don't have the FreeBSD background to know how to probe for the UART.
So before cracking open the case and risking physical damage I would want to:
Step 1: Detect the presence of a UART though software to determine if it exists and what it's hardware is.
Step 2: Determine if there is a driver for that hardware, and if it needs CTS/RTS flow control to operate.
If I get though 1 & 2, then I'd do a test with the box open, and if that passed, I'd worry about making it pretty, but unless I get 1 and 2 figured out first, don't want to put the effort into the physical stuff.
**An aside:
Also, how to you reassemble the unit. I looked inside when I installed memory and SSD, and that heat sink arrangement looked pretty scary to put back together if the motherboard was removed. **
BTW… does your original image file have higher resolution of the components around that connector? When I looked at it, my first guess was that it was power to support a SATA device plugged into the SATA port.
I think your best bet is to switch one of your 8 KVM devices to use the serial console and change your pfSense box to that open KVM connection.
I agree that we should be seeing the serial port show up in dmesg if it was detected on the motherboard. Do you have any serial or com port settings in the BIOS?
I also agree that putting this machine back together may be difficult with the heatsink