QS 20 Serial Port
The IBM QS20 Cell blade (Merrcury systems) has some wacko serial port connector. So what.. well its the ONLY way you can install Linux (or anything) on the QS20. The Serial port and console/media redirection in the blade center console won't work! Not even the DVD-ROM!
So looking at the serial port its a micro-D (molex part number 0834219042). If only Molex would send me a dam cable, IBM won't!
So no one will send you this micro-D connector. What do you do?? Well you bust out the soldering iron.
You'd be happy to know that pin 1 though to pin 9 on the mini serial port port at the front of the QS20 is as per standard serial port pin out. So just solder pin 1 from the micro D to pin 1 on your d-sub.
So its quite easy to solder on 9 wires to a standard serial port . Then you can interface the QS20 with any standard serial port and terminal software, like minicom. I soldered onto the back of the remote serial paddle board. I did not want to make any mods since its not mine. You can un-solder the wire and its gone.
From the below you can see my handy work on the QS20 (note that the serial port paddle port is about 1cm wide) You will need a steady hand. The image makes it look bigger then it is.
The inside of the serial port from a distance :

A close up :
Its not the best pic, but you get the idea. The other end of the 9 wires is soldered into a standard 9pin DIN connector. Its just hanging out the front of the blade via one of the infaband port holes.