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  1.    #1  
    I am new to the board and I have searched every entry for the 755p looking for information related to connecting to the audio out connectors on the bottom if the 755p. I have a standard cradle that has no audio out capabilities. All of the pins are there on the cradle, so i figured I would try to wire up my own 3.5mm jack on the outside of the cradle and plug in some headphones or powered speakers. I have read about the impedance problem, so I am willing to buy an adapter to get it to work if I know I can wire up the headphone jack.

    Does anyone know if this can be done? I have seen different pinouts for treo, can't determine which is correct for 755p. Any help would be greatly appreciated. I will post any results I have.

    Thanks, scott
  2. #2  
    I don't have an answer for your question, but look at this neat charging cradle with speakers for the Treo, on Ebay
    Sprint Treo 755p (blue) with SanDisk 2GB miniSD card. some of my apps installed: TakephOne, DateBk6, 2Day, 4Cast, BellTime 1.0, Palm PDF, Pocket Tunes Deluxe, Kinoma 4, TCPMP, Webmessenger, Card Reader, Slingplayer Mobile, Mobipocket Reader, PS Memo, Virtual Piano, Resco Backup, Cleanup, Uninstall, Destaller, Virtual Piano, Favogo, Snap, Thesaurus, TryDA, Colorize, ChatterEmail, DBFixit, Icon Manager, Noah Pro Dictionary, zLauncher, FileZ, RNS Cuckoo Clock, 25 games.
  3. relgin's Avatar
    80 Posts
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    81 Global Posts

    Here is the info that can get you started.

    Audio Jack Pinout:

    Interface Pinout:

    The Treo 650 and the 755p have the same connectors.

  4. adz1966's Avatar
    150 Posts
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    169 Global Posts
    I have modified my cradle the way you described. PM me and I will send you info.
    The EBay cradle looks nice and it shows a Centro! Has anyone had any experience with this cradle?
  5.    #5  
    That cradle does look nice. If I didn't just buy two cradles( work and home) and and a set of powered speakers for each, I would check one of those out.
  6. #6  
    Man! I wish I were crafty enough to mod my Palm OEM cradles to have an audio output jack! I'd just destroy it if I tried, I'm afraid. French showed me that cradle above not too long ago and it does look nice, but I wasn't able to find any reviews on it. Perhaps I could've if I had looked a tad bit harder, but there were none listed on the Amazon page that I pulled up.

    At any rate, I'd like to see the steps for moding the OEM cradle...I might give it a try. I'd also love to hear anyone's review of the above cradle if anyone has it or decides to order it.

  7.    #7  
    I will post the steps and pictures of what I did if I'm successful in implementing the Mod. adz1966 offered to pass along the info I need, so stay tuned.
  8. #8  
    Quote Originally Posted by graitscott View Post
    I will post the steps and pictures of what I did if I'm successful in implementing the Mod. adz1966 offered to pass along the info I need, so stay tuned.
    Thanks so much, I look forward to seeing your work! Good luck!
  9. #9  
    I would like to see the cradle mod too.
    Pilot 5K->Palm IIIc->Tungsten T/T2->Treo 650/680 -> Pre+ (1.4.5 & Uberkernel)
  10. #10  
    me to - can you post a link with instructions?
    Come Glide with Us

    Rock Solid and Stable - Sprint Centro and Treo 755p
  11.    #11  
    Sorry, tried to post a link to a picture and it failed.

    ... ok I got the picture to display. That's the good news, the bad news is that the mod is not working yet. I think I've got everything wired properly, but no sound. It might be that impedence issue causing the silence, but maybe not. As soon as I get the thing working I will pass along everything I know.
    Last edited by graitscott; 03/11/2008 at 11:18 PM.
  12.    #12

    OK, thanks to some timely help from ADZ1966, I was able to successfully implement the audio out mod on my two cradles. It wasn't too hard, but you do need to be very careful to wire it up correctly, so that you don't short something out on the phone. Basically, the picture says it all, but I will list the steps. This mod as described below works with the Treo 755p. I do not know whether is will work with any other models. If anyone spots anything wrong, missing, please feel free to add.

    I recommend reading the entire write-up before proceeding. Good luck!


    Things you will need: All of the items are available at Radio Shack.( and no, I don't work there or own stock )

    Soldering Iron with very small tip
    Small amount of solder
    2.2K Ohm Resistor ( It was recommended to me to use a 2.7K Ohm, but Radio Shack only had 2.2K Ohm )
    Approx. 8" small diameter wire. Color does not really matter except to differentiate one from another.
    Small piece of electrician's tape
    3.5mm panel mount stereo jack


    1.) Open up the cradle. On mine, this required me to peel off the rubber feet, where the screws holding on the bottom were found underneath. I've been able to remove them several times and they still retain enough adhesive to stay on.

    2.) Remove the screws, and the lid. This should reveal a small printed circuit board holding the pins that connect to your phone.

    I assume that the insides to most of these cradles are the same, but that may not be true.

    3.) Drill a hole in the side of the cradle that will allow the insertion of the panel mount 3.5mm jack. Be very careful not to plunge too far in and damage any wires or boards. Don't ask me how I know that, trust me. Make sure you locate the jack so that the lid can be replaced, and that the connectors do not interfere with and parts inside your cradle.

    4.) You will need to find pins 8, 10, 14, 15 & 16. If you look at my "inside" picture, I have them labeled. My cradle had all of the pins, which is not the case for a data sync cable, so I'm not sure what you will find on other cradles. If you do not have all of the above listed pins present, you won't be able to implement this mod.

    Once you find the aforementioned pins, you can begin wiring it up.

    5.) Cut a piece of wire about 2.5 inches long, strip both sides, one side just strip about 1/16" off, the other side can a bit longer. You want to keep the end that is soldered to the pins very short to prevent shorting out the wire with another pin as they are very close to each other. You can vary the length of the wire to suit the requirements of your cradle. Mine were about 2.5 inches.

    Do this three times as you'll need one for each, ground(gnd), right channel and left channel. I usually put a little solder on the tips of wire just so there is some solder there so you can **** up the wire to the pin without the need to add more solder right away. You can put more on after you get it in place. If you don't have three hands, you'll find out what I mean.

    When soldering the wire and resistor to the pins, you will probably not have room to wrap the wire around the pin. You will have to just **** it up to the pin and solder it. I was able to get a sufficient connection that way. Wiggle it ever so slightly to make sure you have a good connection.

    6.) Solder one wire to pin 14, one to 15 and one to 16. Depending on the orientation of the pins on the board, you may have to angle them. Be sure that you do not short out two pins with the wire or solder.

    7.) Once you have the three wire soldered on the correct pins, now you are ready to solder the other ends of these wires to the 3.5 mm jack. You should be able to find the pinout diagram on the package of the jack to find out which connector goes where. Using the following, solder the wires to the jack. Usually it is at least obvious which one is the ground. In my opinion, if you mix up the right and left it's no big deal.

    pin 14 - L (left) on jack
    pin 15 - R (right) on jack
    pin 16 - Ground on Jack

    8.) After soldering the jack connectors, Remove the threaded mounting ring, and insert the jack through the hole that you drilled in step 3. Place the threaded ring back on and tighten.

    9) Place a piece of electrician's tape over any connections on the board. This is used as insulation so that the resistor does not short out with anything.

    10.) Now take the 2.2K Ohm resistor and solder one end to pin 8 and the other end to pin 10. Make sure you install the resisitor in a manner that will allow you to close the lid without obstruction, and again, be sure to avoid shorting two connectors out.

    11) Visually inspect all of the soldered connections you created. Make sure they are clean and do not short out to neighboring connectors/pins. Make any corrections as required.

    12.) you are now ready to try it out before reassembling the cradle case. Did I mention that it would be a good time to re-check the connections you made.

    13.) Plug powered speakers or headphones into the new jack you installed. On your phone, startup your music player and adjust the sound so that it plays on the internal speaker of the phone.

    14.) Now place the phone on the cradle and after about a one second delay, the sound should start coming out of the head phones/powered speakers. If it does not, go back and re-check the connections.

    Pictures to follow.
    Last edited by graitscott; 03/14/2008 at 10:54 PM.

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