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Old 06-01-2012, 08:31 PM
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Re: Valid replacement charging cable for Fathom

Thanks for answering, pizzaboy192.

I figured out today, using my electronics toolbox
The Fathom, as well as the Apple's gadgets, tries to find out which kind of port is connected to. It does it by sensing D+ and D- voltages, and pulling them up and down. In fact:
  • Before start charging, the phone borrows 100mA. The rest (the following) is done by the phone software, in 100mA units of increment
  • It ask if is connected to a PC, then knows it can draw up to 500mA, else:
  • If the Voltage on the data pins is almost equal (2V open circuit), the phone draws up to 500mA
  • If they're 2.0V and 2.8V open circuit, it draws up to 1000mA
  • In other given scenarios, the phone can ask for more power
What confused me is that with Da_reseboy ROM (don't know about others or the original ROM), sometimes the phone charges with the red LED lit as it supposed to, sometimes it says is charging with the LED off, sometimes says is charging altought it isn't, just saving power, etc. With the 2 wire and 4 wire cable.

So today I opened my car cell phone base/charger. Added some resistors, used a data cable and voila. Phone is working as supossed to do.

Last edited by feliciano; 06-04-2012 at 06:33 AM.
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