I’ve seen Sipeed’s NanoKVM and JetKVM go viral

and it got me itching for something like them for serial consoles. And by something similar, I mean cheap for what it is and hits 80% of the needs for connecting to a serial console over a network. Surprisingly this is a very expensive thing. While I might be searching for the wrong tech, the results I am finding are comically expensive. We’re talking at least $100 for a single port model. I’ve seen some older models go for $25 on Ebay, but they are so old the manufacturer either doesn’t exist or they’ve been sold off so many times, the current company hasn’t any idea it was made by them.

My requirements are that it should be PoE, can be assigned an address via DHCP, and simple telnet that just passes thru the console it’s connected to. Simple yes? No.

This could be kit bashed together with a Raspberry Pi with a USB to serial adaptor. The problem with those options is that by the time you have everything, it’s almost as much as those other single port terminal servers. While you’ll have more functionality in them, in the terms of price, you might as well go with the other stuff because otherwise you’ll go mad keeping things running.

I started this project thinking I’d need to get my hands on an ESP32 board, write up a sketch to do simple a console/telnet proxy in order to get my vision realized. Though I did do that…terribly it turns out that it’s about as cost effective to kit bash together a cheap travel router, cheap usb to console and optionally a PoE splitter or usb hub. Even with adding a PoE splitter, you’re looking at ~$50 outlay. Heck, it’s even more secure since you could ssh into the router instead of being limited to telnet. Plus the usb hub is a killer feature multiplier and makes this an even more attractive route when dealing with multiple serial consoles.

Though the experiment was a failure, I did get to learn some about ESP32 and how to use them. So I guess it was a win after all.