How to find rx and tx

Devin M.

New member
FIND OUT RX & TX BY FOLLOWING METHODS FOR CHINA MOBILES
It is tasted and also you can test it.

1 step is, we need to find GND from phone.

2 step is, we should power on phone (operation with dead phone:
phone must be 100% dead by software)and take multimater put it to voltage.

3 multimeter (-) line put it GND and with (+) line check each connectors
, and usually Tx= 1.8v or 2.8v and Rx=1.7v or 2.7v
(it will be change by processor but strongly 1.7v or 2.8v not 3v or 4v)
This way is too easy and you will save a more time.

For example!
You have got new brand China miracle phone with USB cable. It has got
12 pin. You must find (Infinity team give good Idea 1.2.3 punkts):
1) GND usually it has got 2 GND. (now we have got 10 pins)
2) We will uncheck USB + and USB- (VSS) just with checking by USB cable (now we have 8 pins)
3) By USB cable we also uncheck V bat+, ac adaptor + polarization (now we have 7 pins)
4) Now from this 7 pins you will find 1 or 3 not used pins (last operation we have 3 or 6 pins to find Rx Tx signals)
5) Now at last operation you should use good multimeter just to find Rx Tx with 1.7v-2.7v or 1.8v-2.8v
6) WHEN PHONE IS POWERD OFF TX AND GND WITH MULTIMETER MAKING BEEEEEP
(DIOD TEST OPERATION), WHEN PHONE POWERED ON IT WILL SHOW LIKE DIOD
RESISTANS 600-700 OHM BETWIN TX AND GND.

I think I have give for every body more information
 
Hi!I bought a flash cable and now i want to make it so it connects with my phone (i bought a connector for my phone and a regular chinese flash cable). I'm having trouble connecting the wires as i don't know what pins they should be connected to. Please read below for the details and voltages.
Please help

I used a multimeter and read the voltages on my pins. I now have:
1- 0V
2- 2.63v (maybe tx/rx)
3- 2.69v (maybe tx/rx)
4- 2.78v (maybe tx/rx)
5-3.67v (battery pin)
6- 0v (it beeps when I check resistance, so this is GND)
7- 0v
8- 0v
9- 0.4v
10- 0.5v

Can you please help me decide how to connect my wires to these? I have red, black and green wires. I don't know which should attach to what pin. Is there a way to know wire should connect to which pin by checking the wires voltage???
When I checked the voltages on the wires, I got:
Black- 2.65v (maybe tx/rx)
Green- 0v (i think this is GND)
Red- 3.99v (maybe battery voltage)

Should I put the RED wire to pin 5 and try to read??
 
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