N800 headset button

[rheve]

Their is a small button on the microphone. Does anybody knows what it is used for? Take an incoming call I suspect.

It would be great to be able to use it also for other purposes like "switch to next track" when you are using the N800 as a music player.

[Kny]

I think that's just because they've reused their normal phone headset and just added a new minijack connector. I would be very surprised if any input through the headset connector is accepted. When using a nokia headset connector (used for phones) there are more wires, one of which, I'm sure is for this button.

Good idea though. Another idea - inspired by recent reports on this forum would be to use your (Sony-Ericsson?) phone to remote control your N800. It seems it works right out of the box like on a normal PC. Great concept - I wish Nokia built this into their phones as well

// Kny

[djs_tx]

I believe there are no "extra connectors", otherwise plain headsets would not work in this jack. I think Nokia uses a resistor inside the headset to tell the 770 whether one of the audio channels is an input (microphone) or output (second audio channel.)

The button is a answer / terminate signal for calls that momentarily shorts one of the connectors.

I'm not 100% positive of this, but I believe that is the story.

[johsua]

I thought it was a mute button.

[syrax]

it;s a standart headset , in my Nokia N95 i have 7 buttons ot headset and 4 conector jack to phone but inside in the headset is MCU , i think there is no multy IO in jack for N800 this mus be inplemnted by hardware

sorry for my bad english, REGARDS FROM BULGARIA

[ernia]

"The dial button in the headset answers and disconnects the call. This is implemented by connecting the microphone to the ground."
"Basic headset (headphones + microphone + optional button): 2.5-mm or 3.5-mm, 4-pole connector, left-right-mic-ground, stereo headphones and microphone; optional button that connects the microphone line to the ground (used for call answering, call termination, and voice dialing).. "
http://www.forum.nokia.com/Resources_and_Information/Explore/Mobile_Technologies/Connectivity_&_Interfaces/Wired_Interfaces/Nokia_AV_2.5mm_and_3.5mm_Connector.xhtml

I've read somewhere in the forum that you can use the button to answer skype calls.

[Benson]

Ernia hit the main points, HW-side; the 4-pole connectors work fine with 3-pole cables, the mic input is just shorted to ground that way.

SW-side, it does work in Skype. There's been a couple of solutions rigged to use BT headset's button as some sort of media control, and I believe one of them worked with (or has been adapted to work with) the wired headset's button as well.

[ernia]

i think that the start for a developer to implement media control trough the 3.5 av jack (remember, i'm a newbie, have mercy ...) is this pdf
http://sw.nokia.com/id/81ba2105-f16d-4c2b-a958-542ede07c7bc/Nokia_AV_Hardware_Interface_Specification_v1_0_en. pdf
I was just trying to understand if it were possible to control media player (or mpd) trough an adapter like the nokia ad-54. i think it's really out of my reach.
if something has already been implemented i would like to know, if you can remember it. if not i will search the forum as soon i can get an ad-hoc connection with mer :)

[Baylink]

Yes; the Nokia 3.5mm 4-conductor has a second ring for the mic circuit, normalled to the sleeve as the left and right (tip and first ring, I *think*) circuits are.

[OVK]

I was just trying to understand if it were possible to control media player (or mpd) trough an adapter like the nokia ad-54. i think it's really out of my reach.
if something has already been implemented i would like to know, if you can remember it.

This is something that I am also interested in. Did you find any useful information about this?

[Andre Klapper]

Just throwing https://bugs.maemo.org/show_bug.cgi?id=1553 in here as a potential reference for future devices/plans. Not really helpful though.

[OVK]

Just throwing https://bugs.maemo.org/show_bug.cgi?id=1553 in here as a potential reference for future devices/plans. Not really helpful though.

Thanks for the reference! Interesting reading.

Do I understand this correctly that from the hardware point of view it would be possible to get the the headphone buttons working (play, pause, skip etc.) but some software/drivers are missing?

Is the case for only N8x0 tablets? What about the Nokia 770 or N900?

[speculatrix]

slightly OT. way back when, many computers implemented analogue input for joystick ports by simply having the joystick be a resistor, and this combined with an R-C circuit (resistor-capacitor) which was fed a pulse and a simple threshold detector. The computer simply counted how long it took the pulse to propagate and thus allowed simple measurement of the joystick.

the zaurus microphone input has this feature, and so there's a corded remote control which is really just a bunch of resistors with key switches.

I am wondering whether the input on the n800/n810 also has this feature, or is it really just a binary input?