3 pin Mini-DIN connector
The 3 pin Mini-DIN connector is an important component in preparing a GNU/Linux system for use with hardware stereo. As a part of the NVidia 3DVision kit (see Stereo 3D Display Options), it is required to connect a Quadro-class NVidia graphics card to the stereo IR receiver in order to provide signal sync to the glasses. On a Windows system, the DirectX-based NVidia driver allows for sync through the receiver USB cable; on Linux, which uses OpenGL, the driver requires the older VESA-based standard.
Confusingly, the inclusion of this cable in the 3DVision kit seems sporadic and some kits may not have them. In addition, this specialty cable can be very difficult to find and may be unique to this particular application. If you have purchased a 3DVision kit that did not come with this cable and you wish to use hardware stereo with Linux, this article will provide some guidelines for how to make your own at low cost.
Sourcing components
The original VESA standard made use of the 3-pin Mini-DIN connector to interface with hardware stereo, and the 3D Vision receiver converts that signal into a 2.5mm audio form factor. Both of these connectors can be purchased individually from electronics stores.
- The Mini-DIN connector can be found online at a number of parts suppliers; a male configuration is required for interfacing with the graphics cards. Some examples of sources are here and here.
- For the stereo jack, the easiest method is to purchase a 3-conductor stereo cable in the 2.5mm male-to-male configuration. The number of conductors refers to the number of plastic rings separating the metal parts of the tip. Some examples can be found here and here at amazon.
The 2.5mm stereo cable should be fairly easy to find, and only one side needs to be the correct configuration. Note the 2.5mm port often comes in a 4-conductor configuration (3 plastic rings), as it often connects a microphone in addition to the stereo signal. This configuration has not been tested and is not recommended as it will have an additional wire connection that may prevent proper signal transfer. After you source the cable, cut off one of the ends of the cable and strip back the insulation so that you expose what should be a red wire, a white wire, and the braided shielding for ground.
Splicing the cable
Open the DIN connector to expose the connection plugs for the pins on the inside. The key here is that the pin configuration has to match the signal out of the stereo jack. This information is adapted from the original VESA standard, and has been extended for use with the NVidia 3D Vision system (this author originally found the information from this page here and all credit goes to their hard work discerning the standards). Please refer to that link for a graphic that better explains the orientation of the the pins; however, if you are looking directly at the external side of the connector and the rectangular block is on the bottom, then the orientation of the connection must be:
| Signal | DIN pin | Jack conductor |
|---|---|---|
| 5V Power | Right side pin | Tip of jack |
| Stereo Sync | Top pin | Ring conductor (middle) |
| Ground | Left side pin | Sleeve (braided shield) |
Important! Although the 5V power line is described here, note that the Nvidia 3DVision kit does NOT require the 5V power to be connected (and actually, very likely SHOULD not be connected!), as the receiver is instead powered by the USB connection. In order to avoid potentially damaging the receiver, avoid connecting these lines.
Finally, a multimeter is a good method to ensure the cable is wired properly and with solid connections. Soldering the connections is ideal, but may not be necessary depending on the connector type purchased. Once you have properly spliced the cable together, try it out and see if hardware stereo is working properly on your Linux machine!