FIXING 2.5mm TO 3.5mm CONVERTER OR MAKING UR OWN
hi guys here is a way to fix ur converter.
1. open ur Converter from 3.5mm side.
2. desloder all wires coming from 2.5mm side.
3. take a multimeter or continuity tester.
4. if multi meter, put it on diode testing mode.
5. hold one wire at a time and test it via multimeter(by connceting one end of mutimeter at 2.5mm connector and one end at wire)
6. note the colour and the corresponding connection on 2.5mm jack(where the multimeter beeps and confirm the continuity).
7. Do this for all 4 wires.
8. now u know that which wire is connected from which ponit(connection) of 2.5mm jack.
9. out of 4 wires 2 are for stereo sound, one is common and another one is for mic.
10. Here on my BA the wiring pattern for 2.5mm is 1st is mic, second is spkr, third is spkr, and fourth is common.(starting from silver/golden side see screen shot) as u hv noted the color and conncetion at jack.now u can identify which colour wire on ur 2.5mm jack respond to mic, spkrs and common.
11. Now on ur 3.5 mm jack side u have a mic a button and 3.5mm jack.
12. Button is for attending calls it has 4 conneting points.
13. connect the mic with 2 connecting points points of button (at similer side).
14. connect the another 2 points of button one with common wire(of 2.5mm) and and another with mic wire of 2.5mm. (step 8 helps u here)
15. Now on 3.5 mm jack u have three connections one for left channel, second for right channel and one is common for both.u can identify the common easily as in all 3.5 mm jack the last and larger conection is always for common.
16. connect either left or right connection of 3.5 mm jack with one of the spkr wire coming from 2.5mm jack.
17. do step 16 for another wire for remaining spkr.
18. connect the common of 3.5mm jack with the common of 2.5mm jack(which is one the button).
19. now test ur handsfree.
Precautions and trouble shooting.
1. Remove the enamel insulation from wires porpely else they will not work.For removing, either use some solvent or burn them slightly from edge.
2. Do not short the connections.
3. if ur able to attend the call but ur voice is not going to other side inter change the comnnection on mic cause mic contains a diode which remains in forward bias in only one direction of current. so interchanging of wire will give u opposite polarity which allow the forward and reverse bias in proper direction.