On 12/17/25 19:51, Dan Mahoney via NANOG wrote:
Hey there folks.
Dayjob has historically used USB TTY pods attached to real BSD machines to talk to our cisco consoles, with the amazing benefit that with a program like Vixie's rtty (or conserver) you can also capture the output of those consoles in real-time, and perhaps use that data to identify a connected device.
As a bonus, because the rackmount devices have real DE-9's on them, it means they work with any kind of cable you get (not just your standard rj45 cisco rollover like you might get with a Cyclades thing -- and you don't have to come up with the weird-ass mappings for rj45-serial like you might need like our ME4012 NAS (the serial cable is a stereo plug), our smart power strips (it's either a stereo plug, or an rj12), or something like an older brocade switch (it's a DE9, but it's friggin ODD, and I think it may also be the wrong gender).
It's the wrong gender. It's a DCE pinout on a male connector that's usually used for the DTE. IDK why they did that, and of course they never fixed it because we can't change that sort of thing. That's the only thing "wrong" with it. I know it all too well. You need a null modem cable or adapter AND a gender changer to get to it.
It also means, since you're running a real OS, you have patches as long as the OS is supported (so you're not stuck with "gee it only speaks rsa1024"), versus some EOL appliance. But it's also 2u, and since we're recently buying a lot of Dell hardware, that's Super Overkill for a dell, so I'm evaluating maybe just going "Appliance".
If we stick with an existing unix box for this, I'd want something with proper IPMI/OOB (so Rpi is out) but maybe the dumbest, shallowest-depth atom64 supermicro you can find, in the event you need to do a reinstall or catch a hung system.
A small Supermicro with a Xeon-D or Epyc 2005 series (which are probably still in the works; I have an older Epyc 3151 board that works great, though) is probably a decent option. Should be reasonably cheap; power can be kept to about 50-60W max; they do have IPMI BMC, and get can get a real PCI slot or two for "real" multi-serial cards. They readily fit in 1U. Something like this can also easily handle VPN access to your OOB Ethernet, take a USB-connected cheap LTE/5G modem, etc.
Are there things that other folks are using that are "easy" to work with that you've found to have Long firmware lives, decent warranties and low hassle? Does anything these days actually have DE9s on it?
Depending on the environment, an old Cisco router like a 28xx/29xx with either an NM-16A/32A or HWIC-8A/16A or SM-32A is a very viable option. They're EOL, and I'd not put them on a raw, unfiltered Internet connection, but they offer a lot of options for VPN access to your OOB network (an old ESW module is useful for this) along with the serial ports in a single box, and you'll pay more for the serial breakout cables than you will for the rest of the hardware. You can SSH to them and use whatever line you want, or you can map SSH ports (or telnet ports if you're that kind of person) to individual serial lines (or both). The SSH server...kinda sucks, though. It'll do RSA2048 key exchange (slowly), but the hash algorithms and DH groups it supports are archaic. The pinout on the serial cables is, of course, Cisco which, while not the EIA standard, is as you alluded to the most popular one, so it'll plug directly into most things that have an 8P8C for serial, and adapters to DE-9 are readily available as well. I can't say I'm a Cisco fan, but these old boxes, despite being well past their prime in terms of intended usage, are still quite useful in corners like this, and they're very cheap on the secondary market. There's no modern cellular radio module for them, though I've heard it's possible to get USB-connected ones to work on the 29xx series.