Can't seem to get serial to work

[Polarian]

Hey,

I have spoken about this in #freebsd a few times, but it seems I am
completely incapable of getting it working no matter the responses I
get.

Some background. I wanted serial access through a terminal server (over
SSH) to my servers, because I kept having the tendency to mess up the
firewalling while I was at a conference and being locked out till I
could get back on site to fix it.

Now I do not run server hardware, so I do not have fancy features, my
infra is built on mainly old tech I saved from the landfills.

I originally used two cheap TTL cables soldered together RX-TX TX-RX
and this worked flawlessly, however I also decided to FDE my server and
this can not be decrypted unless you have a "COM" port.

After inspecting the motherboard, I found a JCOM header, this allows me
to connect serial. So I connected a startech plate adapter to it [1]
and then plugged in a nullmodem to it [2] and then connected a through
cable to that.

Server side I see the dmesg log for COM0 [3], and the interfaces. [4]

However whenever I plug the DB9 to USB through cable into any device,
there is no interface which is created, and dmesg shows nothing. I am
honestly clueless of what more I can try.

I am assuming its connected wrongly because the software side of it
looks fine.

Does anyone have ideas?

Thank you,
--
Polarian
Jabber/XMPP: pola...@icebound.dev

[1] https://www.startech.com/en-us/cables/plate9m16
[2] https://www.startech.com/en-us/cables/nm9mf
[3] https://bpa.st/AIIQ
[4] https://bpa.st/KHHA