How-To: Make a Nokia Pop port to female mini jack

When Nokia announced their music player capable phones they neglected to mention the lack of support for external headphones. Since the release of the 6230 and its related family with mp3/aac playback support, many disgruntled users have made their own home-brew cables to plug in headphones. Today we will show one such mod for the Nokia HDS-3 cable. This cable ships with the 6230 and other Nokia phones capable of stereo playback.

Before starting, a quick rundown of some other Nokia models of pop port headphones and audio adapters include:

Nokia HS-3 "Nokia Stereo Fashion Headset" white or black, smaller push to talk unit than the HDS-3, headphones are still of an inferior audio quality
Nokia HS-8 "Nokia Activity Headset" ugly and bad audio quality headphones
Nokia HS-6 "Display Headset" lcd display and controls for audio and calls, but yet again no port to plug in your own headphones
Nokia HS-23 "Nokia Stereo Headset" includes volume control, lesser quality headphones
Nokia AD-15 "Nokia Audio Adapter" allows you to plug in your own headphones, unfortunately this is achieved with a big box on the end of the cable, there is no mic, and as far as we can tell no button to switch tracks.

Even headset models that are not available on the market yet don't allow for the consumer to plug in their own headphones. Why Nokia? Why! For a few weeks we assumed that the audio quality coming out of our 6230 was just as dismal as the headphones in the HDS-3 headset led us to believe. The astonishing part is that no, the audio quality of the 6230 is comparable to most mp3 players on the market once you manufacture your own adapter cable.

The second mistake by Nokia is the misinformation as to how much memory can be recognized on the mmc cards. The manual for the 6230 states the mmc card can be up to 128 mb. In reality the phone can recognize mmc cards up to 1 gig. To see if your phone's firmware is up to date enough to work with that much memory, in the 6230 type: *#0000#. On the screen you should see something similar to:

Nokia 6230
V 05.24
25-11-04
etc.

The important information in this is of course the firmware version on the second line, in this case 5.24. If your phone is not up to date you can have the firmware flashed at most cell phone provider stores. Note that firmware upgrades will wipe the memory of the phone, so be sure to save important info before upgrading. The firmware of the 6230 starting with version 4.44 should correctly recognize 1 gig of memory on the mmc, but may not search the subdirectories on the card for music files to include in the playlist. Before loading audio on the mmc card, we suggest you format it in a card reader on your computer rather than on the phone. Format the card, re-name the card, then fill that 1 gig of happiness with a playlist of mp3/aac and/or mp4 if you have a Nokia model that supports it.

You will need for this how-to: a soldering iron, a knife of some sort, a multimeter, a round file, a Nokia stereo headset (we will be using the HDS-3, but you should be able to extrapolate to another on the list above), a cable with a female mini jack (3.5 mm) connector on one end, or if you have only a cable with a male mini jack connector you will also require a mini jack female to mini jack female adapter. You may also need a small philips screwdriver depending on the model and make of your Nokia headset.

The Nokia HDS-3 (ships with many Nokia models including the 6230):

The HDS-3 has several flavors: the older models have four screws on the back of the push to talk module. If you have this model, first remove the screws. Now for both models, we are ready to pop open the connector. We use a knife to carefully separate the front from the back of the push to talk unit in the middle of the cable:

Once the unit is open, check to see if the speaker is on the front or the back of the unit. Chances are if you have a model with screws, your solder points for the headphones are already visible. If you have the newer model without screws on the outside, you must now carefully pry up the circuit board and flip it over.

If you have the newer model your circuit board should resemble this:

Note the connections on the circuit board. The headphones Nokia supplies are attached to (from left to right) L-, L+, R+, R-. These are the points which we are now going to de-solder:

Your de-soldered circuit board will now look something like this:

Next prepare your female mini jack cable by cutting it to the desired length (we chose a length of about 8 centimeters). This length will be how long the mini jack cable extends out from the push to talk unit. Denude the cables leaving a half centimeter of shielding over the two audio cables. Split the grounding wires into two separate bundles and twist each so they are to the outside of the audio cables:

Determining which is right and left in the mini jack cable is easy if the colors of the cables are red and white. Red is right and white is left. If, like us, you found yourself with a creatively colored cable, notably orange and yellow, bust out your multimeter and a male mini jack connector on a cable that has been similarly denuded. Test the male mini jack connector with a multimeter and note the wiring, for example our male mini jack connector was (where tip is the tip of the connector, ring is the middle, and sleeve is the base):

TIP orange
RING yellow
SLEEVE ground

This meant that our mini jack female connector would have the same pin-out because the female and male mini jack in this case were cut from the same cable. Let us assume for a moment that your male mini jack connector came from a different cable and had this pin-out:

TIP white
RING red
SLEEVE ground

We would then simply plug the male mini jack into the female mini jack and test the cable with a multimeter to determine the pin-out. In the example noted above:

TIP white === orange
male RING red === yellow female
SLEEVE ground === ground

Now we can extrapolate from the fact that on a tip-ring-sleeve style connector the pin-out for L/R/ground is:

TIP left
RING red
SLEEVE ground

This leaves us with the wiring to the circuit board as follows:

TIP left orange
RING right yellow
SLEEVE ground ground

So to solder to our circuit board we will have:
L- ground (remember we have 2 grounds which we split above)
L+ orange
R+ yellow
R- ground (here is the second ground)

Your diagram may be a bit different depending on the colors of your female mini jack cable. A common example would be:
L- ground (remember we have 2 grounds which we split above)
L+ white
R+ red
R- ground (here is the second ground)

As noted above, we split the the grounding cable into two parts. Next tin your cables (prepare them with a bit of solder on them) and trim them down. Solder them onto the points on the circuit board of the push to talk unit following the diagram you have made yourself with the tip-ring-sleeve explanation above:

Now file a rounded notch to let the cable exit out of the top center of the push to talk unit. You only need to file the notch into the backside of the unit (the side without the button):

Next gently push the circuit board back into place. Nudge the new mini jack cable into the notch you've just made:

If you have the older version of the HDS-3 with the four screws on the back, your completed circuit will look like this before you close it back up:

Now snap the two side of the push to talk unit back together, and if you had screws, replace the screws. Alternately, if you wish to change the fugly beige color of the unit, do so before you close the unit. Tape off the button and the base cable. Bust out that black nail polish from your goth phase or some black hobby model paint from that black hawk helicopter you never finished. Alternatively you can pick a more vibrant color to match your colorware computer. Give the unit two coats of paint, leaving time for it to dry between coats. If you don't dig paint, you can also go for the ghetto black electrical tape look (see below for an example). Here is the completed unit (unpainted) with a pair of not-so-stellar sony in-ear headphones and a Nokia 6230:

Version 01 with ghetto black electrical tape, a male mini jack connector and a female to female mini jack adapter and the same not-so-stellar sony in-ear headphones:

The completed new version cable with a delicious pair of Sony pro headphones:

If you are feeling adventurous and in need of analog volume control on the push to talk unit, hop over to hack-a-day to read the advanced How-To. Nokia, if you are listening, please include ports for standard headphones on the phone itself and if not, at least in the cables that are provided with the phone.