I found the ip adress of the management port, and sticking it in a web browser gives me a login screen. It seems it is powered by Avocent MergePoint Embedded Management Software. A search for default login hasn't bought success yet, but I see there may be a way to reset it via the serial port so I'll be looking for a serial cable later! I'm gonna give my ears a rest for a bit and see if I can change the fans next.