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Old 06-01-2007, 06:20 AM   #1 (permalink)
Woodsy
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Join Date: May 2007
Location: Canberra, Australia
Model: 8100
PIN: not4u2kno
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Wink BlackBerry Audio Adapter - Wiring and pinouts

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I've acquired a few 2.5mm plugs (4 ring) from my local electronics store and I'm going to create my own headphone/car adapter.
I'd like to know the pinout, pins and/or wiring for the coupler and adapter.

Here's the info I've gathered in my testing:-

Stereo audio (Confirmed):-
Pin 1 (the tip) is Control +2.4v
Pin 2 is Left audio
Pin 3 is Right audio
Pin 4 is Ground
Pin 1 has a 1.4K ohm loading to Ground and the pickup/mute button shorts Pin 1 + 4 momentarily.

Stereo audio + mic (Unconfirmed theory):-
Pin 1 (the tip) is Control +2.4v and Microphone
Pin 2 is Left audio
Pin 3 is Right audio
Pin 4 is Ground
Pin 1 has a 1.4K ohm loading to Ground and the pickup/mute button shorts Pin 1 + 4 momentarily.

Mono audio + mic (Unconfirmed theory):-
Pin 1 (the tip) is Control +2.4v
Pin 2 is Left/Combined audio
Pin 3 is Microphone
Pin 4 is Ground
Pin 1 has a 1.4K ohm loading to Ground and the pickup/mute button shorts Pin 1 + 4 momentarily.
Possibly swap pin 2 and 3.

Can anyone confirm/enlighten me with this?
Any info would be greatly appreciated.

**** Changelog****
[Edit] - After testing this configuration it didn't work as expected...
[Edit2] - After testing again i fixed my initial mistake... (silly me...)

Headphones work perfectly in stereo with a 2K ohm resistor between pin 1+4. The resistor ohm doesn't really matter as long as it's roughly around 1.4K.

After playing around with the adapter I've come to the conclusion that 2.5mm jack plugs are crap, or the socket in the BlackBerry Pearl that I own is of questionable quality. With such a small plug and it's inherently small surface contact area with the socket, any sideways movement or grease on the contacts will give unexpected results when carrying the phone on person. For car audio this shouldn't be an issue in a stationary dock.

Next task is to figure out how the microphone is integrated. My theory with stereo output is that the microphone is connected to 1+4 but the answer/mute button still shorts 1+4. More testing is needed to confirm this.

Will update as I discover more...

[Edit3] - Added Photo. Pretty sexy huh? Not bad for $5au.
Attached Images
File Type: jpg bb-plug.jpg (27.4 KB, 82 views)

Last edited by Woodsy : 06-01-2007 at 07:14 AM. Reason: Update
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