Palm TX VOIP headset adapter

Ok, it's done. Here are some pics of my latest mod.

I added a 2.5mm headphone/mic jack to an Athena plug to create an adapter for a Nokia headset. So when they get VOIP for Palm working well, I'm in business.


Testing phase.


Everything's in place.


Final product.

Incidentally, there was barely enough space to pull this off because of the type of jack I used. There are smaller jacks, but I liked the look of this one. I used a standard drill bit to enlarge the hole in the connector (twist by hand) and filed off the threads on the jack on opposite sides to get a perfect tight fit. You can see a 10k resistor that connects pins 10 and 8 (TXD to DGND). That connection needs to be made in order to get sound out of the connector. What you can't see is that a single wire connects pins 14 & 15 to the jack, so yes, it is mono sound with both channels.

A bit of a problem was that the \"power\" part of the plug needed some glue on the inside to hold the pins from slipping into the plug when inserted into the TX. I could have left it the power plug section out, but it would have left a hole and having it there makes the fit of the plug tighter. It is a Gomadic brand plug.

That looks great for how it turned out in the end. Did you get to test it for VOIP if you have the app?

I hope you don't mind, I posted this at PalmAttack.

I am/was one of the mobiVoIP beta testers, but when I tried to log on today to test this adapter, I got an error message saying either my username or password was incorrect. So either the beta expired, or they are having server problems. But I have no doubt this would work just fine with the VOIP software; in principle it is exactly the setup I have used before, just a different form factor.

Cool. How did you get the audio input to work? Did you do rewiring for that inside the TX previously?

Does the Hotsync button do anything? I'm guessing not.

Actually, all the wiring is done inside the Athena plug; you do not have to open the TX at all. There are a few threads here and over at Brighthand that discuss installing a mic in an Athena connector. This just uses the same wiring to a headset port instead. The only thing I am adding to the basic mic mod is to also wire the plug for sound out. And, yes, you guessed correctly; what looks like a hotsync button is just a molded mark on the plug case and does nothing.

The only thing I don't know is how this would function on a device that already has an internal mic. I don't know if that would have any effect on an internal mic's functioning or if both the internal mic and the headset mic would be picking up sound.

If VOIP becomes a reality for Palms, it might be worth making something just like this commercially. Hmm..., I wonder if Brando would be interested. He already sells the blank Athena connectors.

Oh, and one more thing I didn't mention above. There are two clips of plastic on the Gomadic connectors that help hold the case shut. They are really easy to bend too far if you close the connector all the way and try to open it again. I haven't had that trouble with other connectors with similar tabs that I've dismantled, but anyone who works with that particularly plug should be careful (or just buy a couple in case you mess one up). Fortunately there are two screws that really secure things well.

Interesting. I knew that the plug was wired for stereo out, I didn't know it also did audio in. This is a very impressive piece of work you did, and it looks nice to boot.

Adama;

Just read your OQO Model 01 review. Good stuff (the review, not that overpriced paperweight!)


Twrock;

Any idea if anyone has yet cracked open a LifeDrive and documented it? I'd like to see where its internal mic leads go. Ideally, the internal mic would be automatically muted when an external one is attached. All the more reason for Palm to do a better job of integrating mics into all of their better handhelds. Something like a T|C2 with wi-fi, BT and NO cellular functionality would make a killer VOIP solution, completely sidestepping the dammed cellular carriers and their glacial release schedule/testing /approval process.

Palm should actually have, as I suggested ages ago, migrated the Tungsten line to a dual wireless VOIP, non-cellular solution a year or more ago. That would leave the Treos as the domain of the cell carriers and the Zire as the unconnected \"classic\" PDA line.

Remember back when Dmitry did the initial mic mod for the TX? He wired it to the "motherboard", not the connector. I suspect he "discovered" where to attach things by looking into a LD or T3 (or at a wiring diagram). I'd think it is much easier and "safer" to solder the leads to the back side of the connector for an internal mic mod, but that might be what makes a difference. I suspect that Dmitry's mod is the "correct" way to do the mod and results in a "standard" system vs. the internal and external mic mods that connect to the Athena connector. But only people like him are going to have the answer to that question. I'm no electronics expert, just a hack who likes to tinker with such things.

If I could bump into someone with a LD, a test would be simple. Just plug in my adapter without a headset attached and see if it will still record sound via the internal mic. But I don't know anyone with a LD, and I have not seen a display model in any stores.

On the other hand, it might not matter much as long as you didn't have the LD in your pocket with all your loose change rattling around it or some other extraneous sound for the internal mic to pick up. Otherwise, you could just rely on the LD's internal mic and use standard headphones for sound. I believe my T2's mic was sensitive enough as long as it wasn't in my pocket. But that's not as handy as having a standard headset for VOIP.

One more note/disclaimer:

Please, please, please, no one blame me for anything bad that happens to your TX if you try a mod based on my experiences. Particularly, I have never had it confirmed to me by anyone \"in-the-know\" the correct way to accomplishing sound out through the connector. I discovered that it worked purely by accident. YMMV and you might end up frying your TX by attempting anything I mentioned above.

Edit: Although what I initially discovered by accident \"worked\", I don't believe it was the \"correct\" way of accomplishing the goal. I have since located Palm's documentation on the multi-connector specifications. After reading that information and experimenting further, I have altered my orginal design accordingly. The original post above has been edited to reflect what is to the best of my knowledge the \"correct\" way of detecting the attachment of an audio peripheral (allowing audio-out through the connector). However, my disclaimer still stands, and I am still not any type of electronics expert.

Getting back to legodude, mobiVoIP still won't let me make regular calls, but at least it let me run the \"echo test\" tonight. So yes, it worked well with this setup.

There has definitely been improvement in the connection since my last test (a couple of weeks ago). The latency is still there, but it was reduced. It should also be noted that I'm probably half-way around the world from their servers, so some latency would be expected. But there has been vast improvement in the \"choppiness\". My voice echo came back quite smoothly with only a periodic \"pop\" and no gaps. Previously is was almost unintelligible with all the popping and spaces and clipping. It's looking promising.

Sorry for the slight hijack.

While the above is undoubtedly an enterprising solution to the mic problem, does the TX not support a headset profile in bluetooth, so you can use a bluetooth headset? - the wireless solution would be slightly more \"21st century\"! If not, it'd definitely be worth consideration in a future Palm firmware update (surely it'd be firmware, as the bluetooth hardware is in place). If my cruddy sony ericsson can do it, why can't my Palm?!

Post-its>71>72>TX

while using the bluetooth headset profile would be the ideal solution to the lack of a mic in the TX, unfortunately Palm's PDAs do not support the bluetooth headset profile natively.

There may be hope, Softick managed to figure out A2DP support so there is a chance.

http://software.palminfocenter.com/product.asp?id=5536

you "suspect" and accuse wrongfully. No need for sarcastic quotes. FYI i do not have LD or T3 to look at, instead i READ THE F*CKING MANUAL!

Not only is dmitrygr a genius, he's pretty funny too!

he he

Wow, that's quite a response. Sorry you misunderstood me, but what you are accusing me of was in no way my intent (being sarcastic). I guess that my use of of words and quotes wasn't clear enough, so let me clear it up by saying I certainly agree with budrowilson and many other that you are a "genius". "Suspect" was meant only to suggest that I was guessing, and I put the word "discovered" in quotes because I couldn't come up with a suitable word. So please, accuse me of not being smart enough to use proper English punctuation and being ignorant of how you work your craft, but not of speaking of you in any sarcastic manner.

In regard to what I think about your abilities, please have a look at what I said about you in this thread yesterday and I think you should be clear that I do not in any way question your ability.
http://discussion.brighthand.com/palmha ... to=newpost
I would suggest that your work is simply brilliant and in that regard you have few peers. These little tweaks that the rest of us do based on your discoveries/research/hard work are nothing more than modified copies of great ideas.

So please, accept my apologies for offending you. It was in no way my intent.