Valid replacement charging cable for Fathom

[feliciano]

I have this annoying message that the charging cable is not suited for this phone unless I use the supplied cable.

Anyone have find out what the Fathom reads to know if the cable is original or not? I would like to pry open and tweak the cable voltage to fool the phone (if that is).

[pizzaboy192]

you need a standard cable for blackberry or a generic usb cable. mine works with any besides motorola ones.

[feliciano]

Well,

I bought a 2 wire charging cable, and sometimes although the power applet say it is charging, it isn´t, and the red LED doesn´t lit.
I tried different charging cables (regular charging and data cables, original from Motorola and other brands and no-brands and this charging only cable) with mixed results. I notice when I do power cycle the phone the things tends to be normal for a while, but after some Wazings and days of use, the problem arise again, and sometimes, power cycling doesn´t help until I use the supplied charger. So I guess the phone somehow knows where is plugged in.

Today I found this article, which makes me think my guess is correct, and I want to share this with you, guys:
How to make your own iPad 2 USB Charger (DIY iPad 2 USB Charger)

[pizzaboy192]

Originally Posted by feliciano

Well,

I bought a 2 wire charging cable, and sometimes although the power applet say it is charging, it isn´t, and the red LED doesn´t lit.
I tried different charging cables (regular charging and data cables, original from Motorola and other brands and no-brands and this charging only cable) with mixed results. I notice when I do power cycle the phone the things tends to be normal for a while, but after some Wazings and days of use, the problem arise again, and sometimes, power cycling doesn´t help until I use the supplied charger. So I guess the phone somehow knows where is plugged in.

Today I found this article, which makes me think my guess is correct, and I want to share this with you, guys:
How to make your own iPad 2 USB Charger (DIY iPad 2 USB Charger)

I haven't had any problems with car chargers that are just generic car to USB chargers, and just ignore the "This charger is not designed for your phone" warnings. The phone still charges and does so relatively well. I made sure to get a 2Amp charger with 2 ports, if 1 device is plugged in, it can get all 2 amps (I also store my phone in front of the air vents so that it can cool while charging) and if both ports are used, each gets 1 amp

The charger cost me about $9 shipped and it hasn't died yet (I think it's a "Dolcia" brand)

You need to check current ratings on your charger to make sure it's putting out at least 1 amp of charge power. Anything less and the phone won't really charge.

[feliciano]

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.

[cpqfe29]

Can you go into a little more detail. what is needed to replicate the cable?

[pizzaboy192]

Originally Posted by cpqfe29

Can you go into a little more detail. what is needed to replicate the cable?

Yes, can you explain what resistors need to be added so that it senses any cable as a valid replacement?
I just had my cable shred a few days ago and am using a standard cable with the OEM charger. It doesn't seem to like my new cable any.