View Full Version : Modifying Stereo Headphones for A925


gregbull
04-10-2004, 06:20 AM
Hi,

I plan to make a 3.5mm to 2.5mm converter to allow me to utilise any (quality) standard headphones to work with my A925. I managed to do the same for my old P800.

The problem is I cannot work out the pinouts (wiring configuration).

Id one of you gurus can post the pinouts for the A920/A925 headphone socket/jack it would be much appreciated.

I am surprised nobody else has asked this, or maybe Im the only bunny that has tried this and can't work it out?? :D

Thanks

Regards


Greg

4bstract
10-10-2004, 11:42 AM
well, i'we locked around for BUYING something.. don't so much up to make things self..

i_sohi
12-10-2004, 03:31 PM
ya man , i thought about it but left the idea thinking why to change these configuration
ru thinking of changing the socket in phone or changing just the pi of any headset?

andrewkeith5
12-10-2004, 04:51 PM
ya man , i thought about it but left the idea thinking why to change these configuration
ru thinking of changing the socket in phone or changing just the pi of any headset?

well, there is a pinout, but you won't get stereo using a normal pair of headphones. the pinout is:

Pin: Same As P800 (I Think)
Ring Arouns Edge: Right Earphone

there u go

lele_haine
11-12-2004, 05:24 PM
Hi guys, this is the first time in my life i post a message that is an answer rather than a question, that makes me very proud :D

The phone can play stereo sound as it does with the original headset, but the pins act differently regarding the headset you plug, a standard mono headset with mic or a stereo headset with mic. The phone can check the type of headset and rearrange the pins to accomplish the model you plugged. The goal is to let it believe you are plugging a stereo headset with mic, while you are plugging just a stereo headphone, otherwise it would recoginze the stereo headphone as a mono headset with mic. letting you hear just one channel.

To build your adapter you just need a stereo 3.5 socket and a 1k ohm resistor, that the phone will see as the mic allowing you to listen a stereo sound.
See the attached images to check out the pinouts. The first image represents the motorola 2.5 jack, while the second one is the connection diagram, on the left you have the motorola jack and on the right you have a standard 3.5 stereo socket, where L stands for Left channel and R stands for Right channel. Ground symbol is shown for completness but it's not connected to anything else.

Hope you'll enjoy this solution, it did function for me!

sorry for my poor english, regards from Rome, Italy!

modex
16-12-2004, 11:26 PM
Hope you'll enjoy this solution, it did function for me!



i might give this a try.. although since i have 2 pairs of earphones i could just cut the 'buds' off one pair and solder the wires into a socket for my headphones

lele_haine
19-12-2004, 09:10 PM
i hadn't any doubt about sacrificing the original headphones, which i found aweful! I don't care about stereo conversation so i just use a mono headset, and with the adapter i built i can use any type of headphones or even connect the cellphone to any kind of device with an audio input (pc, amplifiers, stand-alone speakers) and enjoy my stereo mp3s wherever i am. That's a picture of the adapter.
Post your feedbacks and comments.

modex
20-12-2004, 12:31 AM
yeah.. i'm going to have to buy a soldering iron so i can do that..

what happens though when you get an incoming call? can you just unplug the headphones and answer it or does something weird happen?

lele_haine
20-12-2004, 11:21 PM
yeah.. i'm going to have to buy a soldering iron so i can do that..

Just consider you need a little practice, it's not that easy because the wires are very thin and uneasy to solder. Take the cable long enough to let you have some try

what happens though when you get an incoming call? can you just unplug the headphones and answer it or does something weird happen?

nothing weird happens, the resistor just acts as a mute mic, so nothing wierd can be expected, you can simply unplug the hearphones and answer the call (actually you can also answer the call without unplugging the hearphones, you will be able to listen the caller, but you won't be able to answer back... not much useful :D )

Bysheon
22-12-2004, 05:16 AM
lele_haine>> Oh, how I have longed for someone to describe how this excact sollution is done! :) I am impressed! I want this to work and I will try it, but I am not handy at all. I need some more guiding for this (I am really bad at technical things like this). Could you find it in your heart to make a litte more precise describtion on how you connected the wires? Please? Please? :)

pike2k
27-12-2004, 11:02 PM
is there really no premade 2.5mm -> (stereo) 3.5mm cable you can buy that functions with the A925?

with 90 degree connection on the 2.5mm connector, so you dont have 3cm sticking out of the side of the phone.

zEn0s
09-01-2005, 08:43 PM
is there really no premade 2.5mm -> (stereo) 3.5mm cable you can buy that functions with the A925?

with 90 degree connection on the 2.5mm connector, so you dont have 3cm sticking out of the side of the phone.

No, unfortunately not :frown:





I thought about soldering the microphone between instead of the ohm resistor. would that work? any ideas?

alexderk
10-01-2005, 12:02 PM
i hadn't any doubt about sacrificing the original headphones, which i found aweful! I don't care about stereo conversation so i just use a mono headset, and with the adapter i built i can use any type of headphones or even connect the cellphone to any kind of device with an audio input (pc, amplifiers, stand-alone speakers) and enjoy my stereo mp3s wherever i am. That's a picture of the adapter.
Post your feedbacks and comments.


How did you do that? The wires are too thin! and how did you connect them with the plug?

thx

alex

zEn0s
10-01-2005, 07:48 PM
How did you do that? The wires are too thin! and how did you connect them with the plug?


the wires are very thin but you can use a small pincer to sort them. just use the existing cables which are already connected to the plug.

zEn0s
07-03-2005, 09:16 PM
yay, I finally dared to do it and it actually worked! I get pretty good stereo-sound on each of my ears :D :D

It was not even THAT hard but as i had not muchexperience of using a soldering iron before, it was difficult for me.

I used a Nokia N-Gage Adapter (ADA-2) and the original Motorola A925 Handsfree, an 1k Ohm Resistor and a lot of soldering tin! I attached some pictures of it.

I also found out, which wires are connected to which part of the jack. I showed that in another attached picture.

OK, I ope I could help some people who have the same beginning problems like i had!

greets, Dietmar

Bellers
01-10-2005, 07:05 PM
I have been trying for quite a while to attact a 3.5mm stereo socket to my motorola a1000 and this is the first place I found that has given me much help. I was just wondering whether this method would work on a a1000 since they have a slightly different connector. it is a 4pole 2.5mm jack plug (similar to a standard headphone plug but smaller and with 1 extra black ring). If anyone could help me with the pin outs of this plug I would appreciate it very much!

djcarlox
08-01-2006, 07:01 PM
:con? IS IT THE SAME WIRE SETUP THAT A1000? A GREETING :)

Denisuk
24-02-2006, 03:00 PM
Hi all. I have a troubles with handsfree. I brought a925 with stereo handsfree from E398. So phone detects it, but plays mono sound. And when i'm speaking within handsfree - my collocutor listens himself louder, then me. So i need new 2.5 jack?
e398 handsfree has that pinout:
http://users.cosmostv.by/denisuk/handsfree2.jpg
How can i change that handsfree to play stereo?

Patheticpaul
02-03-2006, 05:11 AM
I'm doing a custom wiring harness/plug for my motorcycle helmet intercom system. How would I wire the microphone going through a push to talk button? What type of button would it have to be?

dakiro
15-05-2006, 12:59 PM
is there really no premade 2.5mm -> (stereo) 3.5mm cable you can buy that functions with the A925?

with 90 degree connection on the 2.5mm connector, so you dont have 3cm sticking out of the side of the phone.
there are convertors but unfortunatelly not compatible with this weird connection, you can however open one and try to change it, here in poland they cost about 50 cents.

Scorin
16-05-2006, 05:00 PM
thanks you all:D
I made one with a mic btw I used the original mich and bottom from the stereo headset.
works perfect:)

dakiro
17-05-2006, 11:18 AM
i have just finished doing the headphones converter, it works pretty well, just need to give it some finishing touches,(so that it looks a bit better)

the mic works as well (the button in it as well)

The thermo-shrink wrapper is a good idea for this one, just get the right colour and don't forget to put it on before soldering (unlike me) because then you will have to do it once again (like me)

good luck!

Thousandarm
20-07-2006, 12:26 AM
Maybe this unfinished instruction manual can give you all some ideas sorry that there is no pictures.
HOW TO MAKE AN ADAPTER TO USE YOUR PC HEADSETS WITH ANY PHONE (CELL PHONE), WITH A STANDARD HEADSET JACK. (In other words how to make a simple yet multi functional adapter that accepts two 3.5mm plugs and that then plugs into 2.5 in phone jacks)

Why would you want to do this?
There are many reasons to make this adapter. The adapter allows you to plug many devices into your phone and use the direct audio from your phone in many ways. The main reason for most people is to be able to connect your PC headset to your phone.

How to build it.

Get these parts (See picture). (They are sold at Radio shack and other hardware stores and the items numbers from radio shack.)


1. One 1/8 Stereo Plug – Item # 274-869. That is the one with screw terminals, but you can also use the jack without screw terminals, that is just made for soldering).
2. Two 3 conductor stereo 1/8 (3.5mm) phone jacks – Item # 274-373 (that package comes with 2). You can also use the longer covered and protected type of jacks, but they are harder to solder.
3. One 1/8 to 3/32 adapter – Item # 274-373 (this is the 3.5 to 2.5 converter and it will have two rings on the male part.) Do not get the mono—one ring style adapter.
4. Different colored small wires (you only need a few inches of wire). You can cut and splice wire from an extra phone chord. That works great.
5. A PC headset. Logitech or any brand with the two 1/8 plugs on the end. One of those plugs is pink and the other one is usually colored black (but sometimes green).
6. A cell phone or a telephone with standard headphone jack.


The tools you need are:

1. A wire cutter (or scissors)
2. A soldering iron and electrical solder
3. Electrical tape
4. A small Phillips screwdriver (only if you got the plug with screw terminals—which I recommend. As seen in the pictures)


Procedure

1. Cut your wires:
Cut each cut about 2 inches long. You will need a total of four wires. Two of the four wires need to be the same color (this will be for the ground terminals), and the other two to be of different colors (these will be for the mic and the headphone speakers). In the picture below I have two yellow wires, ones blue, and one red.

2. Attach wires to the 1/8 plug.
(This is a special procedure because the cell telephone jack uses one channel to carry the sound out to the headset earphones and the other channel to carry sound in from the headset microphone. Therefore the plus is wired so that these channels can be distinguished and then in step 3 these each of these 2 separate channel wires go to its own 1/8 (3.5mm) phone jack).

a. Unscrew and take apart the 1/8th plug. Do not loose the case and plastic liner.
b. Connect the two wires of the same color to the longest terminal. Either screwing or soldering. I twist the wires tightly together first so there are no frayed copper filaments sticking out. The longest terminal of the 1/8 plug is the called the ground terminal. To explain the procedure I call both the wires that have the same color the ground wires, there are two of them because the ground needs to connect to both Jacks as shown in step 3). ( in the pictures below you can see that two yellow wires were attached to the longest terminal).
c. Connect the two wires you have left (they each are a different color) to the two remaining terminals which are closer to the top of the plug jack. One connects on the right terminal and the other on the left terminal. each receive one wire of a different color. (In the pictures below these are the blue and the red wires).
d. You can solder these connections (solder if you feel the screws are not enough) or you may have to solder them if you are using a non screw type of plug.
e. Put back the plastic liner around the connections you just made and screw the other parts of the jack back over the finished connections. Now you should have all of the wires coming out of the back of the 1/8 plug.

3. Attach the other end of the wires to the two 1/8 jacks.

a. Attach the ground wires to the 1/8 (3.5mm) phone jacks. These are the wires that you have two of the same color), There are two because one goes to each jack. Attach this ground near the top of each jacks. (that terminal corresponds to the connection that touches the base of the plug when the male plug is inserted into the jack.)
b. Attach the colored wires to the 1/8 (3.5mm) phone jacks. Once wire goes to each separate jack,
• First you need to prepare the jacks for the wires by squeezing the ends of the bottom terminals on the jacks closer together with your fingers. (You cannot squeeze together the bottom terminals if you chose to a different model jack. That is why I prefer to use the radio shack model jacks that are shown in the picture )
• String one of the singularly colored wires through the holes on the bottom of one terminal that you just squeezed together. You need to fish it through both holes. After you fish it through, you can bend and tie it around is you are skillful. Repeat the above procedure with the other color wire and the other jack. Note: By squeezing the terminals and putting the wire through the holes you connecting the “right and left” channel of on each jack you enable the equipment to work optimally. Both ears of your headset will have the sound and the mic from your pc headset can deliver its full signal into the telephone or cell phone. (so if you are using a different style of jacks in this step you need figure out how to string the wire to connect both right and left terminals and then solder them).
In the picture below you can see the blue and red wire are used in this step. You can also see that the blue and red wires are connected into different jacks.
c. Solder all of your connections

4. Test for the audio out – The moment of truth!!!!
Now that everything is wired. You can test which jack that you made is the audio out and which is the mic in. After you figure out which is which you label these jacks so you always know which plug from the headset goes into which jack.

a. Plug the 1/8 male plug into the One 1/8 to 3/32 adapter and plug that adapter into a standard cordless telephone or cell phone headset input jack.
b. Plug the black (or green) 1/8 plug your headset into one of the 1/8 (3.5mm) phone jacks that you just wired. (do not use the pink plug).
c. Put the head set on and hit talk on the phone, or if you are using the cell phone either call you voice mail or do something that produces sound.
e. Either you will hear some of the sound/dial tone or you will not. If you hear a dial tone or your cell phone then you know that that jack you are plugged into is the audio out (for the sound that goes to your ears.)
f. If you heard nothing in step e, then take the black (or green) headset plug out and plug it into the other 1/8 (3.5mm) phone jacks that you made. You should hear the dial tone/sound or voice mail. Whichever jack that did not produce sound in the head set is for the mic. You should label the jacks, “ear and mic” so you can remember which one correspond to the mic (pink) and which to the earphones (black-or-green). You can see in the picture that I wrap colored tape around the jacks. It would ideal if you used pink and green colors for this is becoming the standardized colors. Pink for mic and green for audio out.
g. In this test \Did you notice how great the sound quality was? It should have been in both ears of the headset, loud and clear

5. Finishing up
a. Wrap the jacks in electrical tape so that the connections are not exposed.
b. Attach the finished jacks to the plug using tape.
c. As described above use colored tape or a pen to label your nifty adapter for ease of use.
d. Plug into your phone and enjoy.

Other benefits of this jack.

Since you can connect any speaker or microphone that has a 1/8 plug into this jack, you can connect most anything to your telephone or cell phone. This enables you to do many things such as running a line into your computer.

bitman
11-01-2007, 02:41 AM
You rock.

I had a 3 ring jack some wire and a 1/8" plug on a bench and for the life of me I could not figure the pinout. Pissed me off but good.

The 1k resistor makes sense and explains the trouble I was having trying to mate stereo headphones to my Motorola v710.

If I backed a 2 ringer (stereo jack) out of the plug, voila! stereo, but it does not stay there as you might figure. So I was sure I could simply wire it up but no....

And the case on the plug is'nt ground!!! WTF is that!!?? :D

Thanks.

:LSB

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