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According to the transformer provided to power the Linksys SPA-3102 VoIP gateway, it expects 5V and 2A MAX.

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To avoid having two devices on my desk, I was thinking of stripping the 3102 of its case, put it into a PC case and use the PC's PSU to power the Linksys using one the Molex plugs.

Does someone know if the plugs coming out of a PSU is compatible with what the 3102 expects?

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This is definitely possible, although I don't consider it to be a good idea.

The voltage and current draw from the gateway can easily be accommodated by the Molex hard drive power plug. You will need to get a plug for the molex connector and use a plug that fits your gateway (make sure the power and grounds are correct). Then connect the wires up. The 5V is red and the GND is black. Normally, I would solder the connections and use electrical tape to cover up anything conductive.

The issues I can think of doing this are:

  • Putting the box inside the chassis may affect the thermal profile of the system and cause it to run hot or overheat.
  • Something loose in the chassis may also cause damage to components.
  • EMC may be a problem because the gateway was designed to be in a case. Removing it from the case may let the radiated noise affect the system's functionality or vice versa.
  • You'll likely have wires for the gateway running into and out of the chassis.
  • If the gateway hangs for whatever reason, it'll be a pain to unplug and power back up.
  • You can't see the gateway status lights unless your chassis has a clear opening.
  • Adding a box that connects to other lines in the house such as the telephone can introduce another way that lightning or a power surge could enter your system potentially destroying your computer and your gateway.
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Thanks much for the commments. I guess I'll give up because I just don't have the skills to make sure the thing works OK :-/ – OverTheRainbow Sep 29 '09 at 13:29

That sounds like a lot of engineering just to keep a tidy desk. While It's admirable that you have a "think out of the box" attitude, my recommendation would be to use the power adapter that comes with the unit, in the manner it's intended to be used. Unless you're an electrical\electronics engineer I find it's best to leave that kind of borking to the pros.

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I guess I'll give up, but I'm still curious to know if it's possible to use one of the Molex plugs to power unusual devices like the Linksys above. – OverTheRainbow Sep 24 '09 at 10:29

It is clear from the picture that the device accepts a cylindrical power connector. There're no such connectors inside a PC. See

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