I always seem to forget this one.
To pass F11 or F12 over a serial connection (either real serial or Serial-over-LAN IPMI), it’s Escape followed by ! (Shift+1) or @ (Shift+') respectively.
Note that on a US keyboard ! and @ would be next to each other above the 1 and 2 keys so that would make some vague kind of sense as alternatives to F11 and F12. But it’s literally the @ that matters and since I’m using a UK keyboard then it is Shift+'.
(╯°□°）╯︵ ┻━┻)
TL;DR: Most motherboards have a serial header in an IDC-10 (5×2 pins) arrangement with the pins as a row of even numbered pins (2,4,6,8,X) followed by a row of odd numbered pins (1,3,5,7,9). Supermicro ones appear to have the pins in sequential order (6,7,8,9,X and then 1,2,3,4,5). As a result a standard IDC-10 to DB-9 cable will not work and you’ll need to either hack one about or buy the Supermicro one.
A comment below kindly points out that Supermicro actually is using a standard header pinout, it’s just that it’s a competing and lesser-used standard. It’s apparently called Intel/DTK or crossover, so that may help you find a working cable.
I bought a Supermicro motherboard. It doesn’t have a serial port exposed at the back. I like to use serial ports for a serial console even though I am aware that IPMI exists. IPMI on this board works okay but I like knowing I can always get to the “real” serial port as well.
The motherboard has a COM1 serial header, and I wasn’t using the PCI expansion slot on the back of the chassis, so I decided to put a serial port there. I bought a typical IDC-10 / DB-9 cable and plate:
Didn’t work. Serial-over-LAN (IPMI) worked alright. On COM1 I would get either nothing or a run of garbage characters from time to time. I wasted a good number of hours messing with BIOS settings, baud rates, checking if my USB serial adaptor actually worked with another device (of which I only have one in my home), before I decided to sit down and check the pin numbering for both the header and the cable.
Looking at the motherboard manual we see this:
And the cable?
Notice anything amiss?
The cable’s pins go in a row of odd numbers and then a row of even numbers:
2 4 6 8 X
1 3 5 7 9
-
The X is the missing pin (serial uses 9 pins) and the - indicates where the notch for the connector would be: next to pin 5 in this case.
The header’s pins go in sequential order:
6 7 8 9 X
1 2 3 4 5
-
As a result all but pin 1 are incorrect.
You actually need a Supermicro cable for this. CBL-0010L is the part number in my case. CBL-0010LP would be the low profile version. Good luck finding it mentioned on Supermicro’s site, but your favourite reseller will probably know of it. As it was I found one on Ebay for £1.58+VAT, and it works now.
After knowing what to search for I also found someone else having a similar issue with a Supermicro board.
You could of course instead hack any existing cable’s pins about or fit an adaptor in between (as the person in the above link did).
Thanks Supermicro. Thupermicro.
My OneRNG kickstarter arrived today. I had five units, so I chose three external models and two internal ones. The finish of the external model isn’t really up to the quality of an Entropy Key. Here’s a picture of them together.
Given that the external model looks rather flimsy — I could imagine it getting snapped in half if someone bumped into it — I think I’d probably prefer the internal model in practice. Here’s what that looks like:
The three different connectors are to try to ensure you can find a useful connection angle no matter how your motherboard’s internal USB headers are laid out.
I haven’t yet plugged them in to check out how they work. This is probably going to have to wait a few weeks as I have quite a lot on.
Assuming they work about as well as the Entropy Keys then I only need to keep two of these for myself, so if anyone wants one I would be willing to sell it on to you at cost plus postage.