How to create a EMU to 3.5mm headphone jack adaptor


  1. crankin

    crankin Member

    Just a quick guide to show how i made an adaptor out of the original G1 headphones for 3.5mm headphone jack.

    First off just some background

    [​IMG]
    Above is "EMU" connecter (EMU stands for Enhanced Mini USB) this connector is pretty much the same mini-b USB connector except EMU also has an audio channel.

    In the above image:

    Data
    A = GND
    B = NC
    C = +DATA
    D = -DATA
    E = +5v Audio
    1 = +Mic
    2 = +Right
    3 = Switch
    4 = Gnd
    5 = Gnd
    6 = +Left

    Now for the creation of the adaptor:

    1) Cut the cable as near or far away from the EMU as you like (i made my adaptor about half a foot long in case i had to start again)
    2) Strip the cables and split them apart

    1 Mic = white
    2 +right = red
    3 switch = blue
    4 ground = blue/copper
    5 ground = copper
    6 +left = green
    A ground = red/copper

    [​IMG]

    3) Next up you'll have to find a 3.5mm headphone jack to use (i work for a laptop repair company so i just got one off an old mainboard)

    4) On the picture above you can see where you need to solder the the left and right speaker ( please excuse the inaccuracy of the image BLUE in this case is ment to be GREEN, and the BLACK PCB wires are GROUND/EARTH)

    Just a note that only one ground is really needed, i used PCB pin 2. Also, this guide is ONLY for headphones, if you want to use the other features of the EMU (like mic) you will also have to connect those and use a diffrent type of 3.5mm jack.

    5) Now just seal the wires with some hot glue and cover it with some heat shrink and its all done!

    Please post any questions and please point out if ive missed anything.

    Pictures of my finished product to come! Please also excuse any spelling/grammer errors and the poor english in the subject line:p

    Advertisement
  2. Ageless Stranger

    Ageless Stranger Well-Known Member

    Hey Crankin, thank you very much for taking the time to research and post a concise howto. I am sure there are quite a few applications where this can be very useful, cheers.
  3. justjimjpc

    justjimjpc Premium Member VIP Member

    Here is some additional info ...

    Pin B is used to recognize original charger when connected to ground (pin A) or tied HIGH ...

    Verizon is using (B to +4.1 volts) this to prohibit any charger other than their overpriced - high profit units.

    One benefit that could be used by a device is to hold "B" at a none valid state say +1.5 Volts ... then when a battery has reach a predetermined level (current draw, temp ) is to then pull this (B) pin to ground and thereby preventing a dumb charger or dumb batter from becoming over-charged.

    Another find is that : pin4 is linked internally to pinA (gnd) in the plug assembly and this is how the device detects a headset connection, by tying the Data And Audio Gnds together.
    So if you are trying to kludge a headset plug for use as a charger connector .. you will need to cut the link between pin4 and pinA .

    ==============================================================
    found an interesting adapter..
    3-in-1 11PIN ExtUSB Headphone Handsfree Adapter for HTC / O2 Xda
    Product Model: [ad11ext3in1]
    3-in-1 11PIN ExtUSB Headphone Handsfree Adapter for HTC / O2 Xda / Dopod / Qtek / T-Mobile / i-mate / Cingular devices:
    Link : Product Info - eTech-City.com - Wholesale & Export Professional Accessories & Gadgets for Electronics at Factory Offers

    ===================================================================
    found a do it yourseld Product Information Unsoldered HTC ExtUSB 11pin USB Connector, Comes in 3 Pieces. Easy to Assemble. Fits lots of phones :
    PodGizmo - Gizmos for the Technology Generation

    ====================================================================

    Attached Files:

  4. N3TWORK BURN3R

    N3TWORK BURN3R Well-Known Member

    Oooh! A DIY! I love these things. I think im gonna make one, just for fun. I have 2 Tmobile cables and 3 small adapters. But making them is the fun part.
  5. crankin

    crankin Member


    Might want to hold off sorry! i have noticed an issue while using the adaptor, i beleive i might have screwed up some of the cabling because im only getting mono sound out of both headphones. I'll post back as soon as ive fixed it
  6. justjimjpc

    justjimjpc Premium Member VIP Member


    Did you tie both EMU connector's Audio pins 4 & 5 (Gnds) together ?

    I think they need to be !!!
  7. crankin

    crankin Member

    From memory i think i just used one gnd :confused: do you think tie both in?
  8. justjimjpc

    justjimjpc Premium Member VIP Member

    Both EMU connector's Audio pins 4 & 5 (Gnds) should be tied together ?

    I think they need to be !!! ... it can hurt and may be your problem.
  9. ravens0ng

    ravens0ng Well-Known Member

    Nice info!

    One of the first things I did when I got my G1 was to do a similar mod, replacing the crap earbuds that come with the phone with some decent sennheiser buds, desoldering the old buds where they attach to the mic unit and swapping them out with the new ones. That solves the mic not working on a mod like this. That mod is on this forum somewhere also.
  10. justjimjpc

    justjimjpc Premium Member VIP Member

    I need to try to find that so I can locate these close to each other in a FAQ library ..

    If you can find the other let me know with a link posted here .. Thanks
  11. ravens0ng

    ravens0ng Well-Known Member

    I was mistaken, that mod was not on this site; here is a link to it.

    Make: Online : "Upgraded" G1 headset - use whatever earbuds you want...

    The mod went flawlessly, only trick was to use tons of flux, and pre-tin the cloth wire, as it is not very conducive to soldering. Also, having my wife hold the mic unit while I soldered was a HUGE help. I managed to do 2 pairs in under 15 minutes.
  12. justjimjpc

    justjimjpc Premium Member VIP Member

    Thanks .... I was driving myself silly looking for it .. :eek:

Share This Page