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This page contains instructions on how to add a serial port (a DB9 Female DCE port) to a Linksys NSLU2 (“Network Storage Link for USB 2.0 Disk Drives”).

THIS WILL VOID THE WARRANTY ON YOUR NSLU2.

The DB9F (Female) connector is wired as a DCE (think of this as a peripheral serial port), and can be connected directly to the serial port on a host PC. This gives you access to the built-in serial console on the router (115200, 8, N, 1).

Note that the serial port does not support hardware flow control (it’s not pinned out on J2 on the Linksys PCB), so you need to use software flow control when connecting to these ports.

Requirements

• Linksys NSLU2 Network Storage Link
• AD232DBH Max232 adapter kit (3V version)
• 4 pin Single-In-Line IDC male PCB-mount header
• 4 pin Single-In-Line IDC female cable-mount header
• Some wires (see the pictures for details)
• A soldering iron and some solder

Remember, this will void the warranty on your NSLU2. I take no responsibility for your actions.

Instructions

1. Open up your NSLU2. This step will void the warranty on your NSLU2.
   • There are no screws – the case is held together by small tabs along the vertical junction between the light grey and dark grey parts of the case.
   • Hold the NSLU2 upright in front of you, with the vertical side of the case with the rubber feet facing you, and with the rear connectors on your left, and the front LEDs and power switch on your right.
   • Gently squeeze the dark grey sides of the unit with your left hand thumb and forefinger just about where the uppermost rubber foot is on the left hand (or rear) part of the case, and with your right thumb and forefinger pull the top of the light grey part of the case away from the dark grey part of the case, wiggling the light grey part as you pull it. It should start to separate at the top of the unit at the boundary of the dark grey and light grey parts of the case (about a millimeter separation is all you are looking for at this stage, don’t try and separate it more than a millimeter or you will break the tabs). You might even hear a soft “click” as the tabs near the topmost side rubber foot are dislodged, but don’t be concerned if you don’t hear the click in this step – you will definitely hear it in the next step.
   • While continuing to apply gentle pressure on the case so that the slight 1mm separation remains at the top, move your left hand thumb and forefinger down to the middle of the case to the top of the area with holes in it (just under the “Linksys Network Storage Link” text on the sides of the unit) and continue gently squeezing the dark grey part of the case whilst gently pulling and wiggling the light grey part of the case.
   • At this point, the top-most tabs will definitely be dislodged, and the middle tabs may also come apart. The separation at the top of the unit at the boundary of the dark grey and light grey parts of the case will now be about 3 or 4 millimetres – again don’t try and separate the case at this point or you will break something. You will now be able to clearly see the tab near the top-most rubber feet. There is one set of tabs at the top near the rubber feet, one set in the middle just below the top of the holed area, and a third set of tabs at the bottom of the case (just above the bottom set of rubber feet).

   

   • Again, move your left hand thumb and forefinger down to the bottom of the left hand (or rear) part of the case, just on the bottom set of rubber feet near the boundary of the dark grey and light grey parts of the case, and move your right hand thumb and forefinger down to the bottom of the right hand (or front) part of the case, this time grabbing the bottom front dark grey curved section (on the sides of where the power switch is).
   • This time you should squeeze (with the left hand) quite a bit harder than you needed to for the other two sets of tabs, and instead of trying to angle the top of the light grey part of the case away from the top of the dark grey area of the case, you are now trying to pull the bottom of the right hand (or front) part of the case away from the left hand (or rear) part of the case so that the two parts of the case are separated by a vertical gap of about 3 to 4 millimetres equally from the top to the bottom.
   • All three sets of tabs should now be dislodged, and you should be able to slide the two parts of the case apart. The right hand (or front) part of the case slides away freely, with the PCB remaining in the left hand (or rear) part of the case.

   

   • You can now just slide the PCB out of the left hand (or rear) part of the case, and you are done.
2. Solder the 4 pin IDC male PCB-mount header at J2 on the board, as shown below. This step will *really* void the warranty on your router. This is the only soldering you need to do on the Linksys PCB. You might like to re-assemble your NSLU2 and test it out just to check that it still works after this step.

   

3. Build up the AD232DBH kit as per the instructions provided with the kit.

   

4. TBD …
5. Thread the 8-pin header through the Disk1 opening in the case.





6. Plug the header onto J2, re-check all connections and reassemble the case.

If you find any ambiguous or non-obvious instructions on this page, or have any trouble at all in following the instructions, then please let me know.

Did I mention that this will void the warranty on your NSLU2, and that I take no responsibility for your actions? Sure I did. Don’t bother sending your legal folk my way …