Cheap multiport terminal servers are available surplus.[1] This one is $69 for 24 ports. You'll need a 48VDC power supply for it, though; this must have been for a telco installation.

[1] http://www.unixsurplus.com/product/digi-cm-32-console-termin...

I'd love an open/non-shit IP-KVM, too. Right now it's basically a Raritan vs. Avocent duopoly (with lots of other rebrandings), and then IPMI (which is the right choice for huge numbers of homogenous machines, but wrong for a test lab).

This would pair like fine wine with http://www.conserver.com/ to make a distributed console server system for large infrastructures.

Turn an old Linux pc into a terminal server: https://github.com/jhallen/joes-sandbox/tree/master/utils

(look for serial connect / c.c)

This lets you telnet to a serial port (uses xinetd and telnetd), just like commercial ones. It includes locking and a way to force disconnect of an inactive user hogging a port. I think it should work on the raspberry pi / Freetserv.

Other features: hex dump mode, suppress ansi mode, logging, reports name / ip address of user already connected to port.

Also there is a script to control the outlets on this device: http://www.cpscom.com/controlled-ac-power-strip-cps-468.html (which is the cheapest computer controlled outlet strip I could find).

The idea is you can connect to the console port of some machine under test. Once connected, you can also control its power. This is great for working on hardware remotely or linux kernel development.

Using a raspberry in one of these would make me scared that it won't come back after a power cycle because it has inevitably killed the filesystem or SD card.

A MIPS system from a router running OpenWRT would be a good fit, they usually boot from read-only mounted rock stable flash and have proper networking hardware.

I haven't looked at the details of this design but from past experience, I've found USB based serial ports to lose data at high speeds. I tend to use PCI/PCIe based cards instead.

This is very cool. I'm amazed at how expensive it is even built yourself. How much is the equivalent professional version?

What I would be interested in is:

USB HUB, 10-20 Ports

Each Port switchable

19" Rack-mount case

Was once available from a Russian company for an insane price (2k US$).