4 Pole Audio I/O Connections For Macbook Pro... Post: 302809377

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Operating Systems OS X (Apple) 4 Pole Audio I/O Connections For Macbook Pro... Post 302809377 by wisecracker on Sunday 19th of May 2013 02:47:08 PM

05-19-2013

Registered User

4 Pole Audio I/O Connections For Macbook Pro...

Disclaimer:-

You take this information and use it ENTIRELY at your own risk.
I and this site hold no responsibility for any errors either in this text or with your electronics capabilities...

The reason I have given this away is/was because I needed an audio input for a simple MacBook Pro
Python Audio-Oscilloscope I am developing.
(This is also shown in a different guise at the end of the AudioScope shell script too.)

BEST VIEWED IN PLAIN TEXT!

Machine:- Apple MacBook Pro 13 inch.

OSX 10.7.5...

Vintage:- August 2012.

Common 3.5mm, 4 pole, Mic/Ear socket cable for external MONO audio input, (and
stereo audio output)...

Code:

Plug required, (or similar)...

http://www.ebay.co.uk/itm/3-5mm-Mini-Jack-Right-Angle-90-Degree-Solder-4-Pole-Male-Plug-Connector-/320770305756

Resistor, 2K2, 1/8 W, 10% tolerance...

(2 x Resistors, 33R, 1/8W 10% tolerance...)

Code:

This is the wiring for the auto-switching of the Mic input to external...

Pins.               Wiring.
-----    TIP        -------
 1 ---->  O  <----- Left Audio Output +ve.
 2 ---->  H  <----- Right Audio Output +ve.
 3 ---->  H  <----- Mono (Mic) Input, Active.
 4 ---->  H  <----- Common To All Inputs And Outputs.
         ---
        |   |
        |   |______
        |__________|=========

For the auto-switching capability a 2K2 resistor must be connected across Pins 3 and 4. [Mono (Mic) Input, Active and Common]...

Test by plugging into the socket and check that the "System Preferences > Sound" switches over to external input and output.

You now have two audio outputs at low impedance and an analogue audio input at around 2K2 _impedance_.

Do NOT drive the input with more than 100mV AC and do NOT connect to a DC _supply_ either.

Do NOT load the audio outputs with less than 33 Ohm resistors.

Do NOT assume that Common is connected to GND, Ground, of the computer, although it may well be.

I am assuming that if you are capable of doing this that you are also capable of doing the subtle level tests etc...

(C)2012, B.Walker, G0LCU. (Issued as Public Domain for all.)

Enjoy finding simple solutions to often very difficult problems... ;o)

wisecracker

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LEARN ABOUT SUNOS

gnome-audio-profiles-properties

gnome-audio-profiles-properties(1)				   User Commands				gnome-audio-profiles-properties(1)

NAME

       gnome-audio-profiles-properties - the GNOME audio profile manager

SYNOPSIS

       gnome-audio-profiles-properties [gnome-std-options]

DESCRIPTION

       gnome-audio-profiles-properties	enables  you to configure and create audio recording profiles. Audio recording applications such as gnome-
       sound-recorder use these profiles to determine how audio should be recorded and stored to audio files.

       New audio profiles can be created, and existing audio profiles can be either edited or deleted using the GNOME audio profile manager.

OPTIONS

       The following options are supported:

       gnome-std-optionStandard options available for use with most GNOME applications.  See gnome-std-options(5) for more information.

EXAMPLES

       Example 1: Launching the GNOME Audio Profile Manager

       example% gnome-audio-profiles-properties

EXIT STATUS

       The following exit values are returned:

       0	Application exited successfully

       >0	Application exited with failure

FILES

       The following files are used by this application:

       /usr/bin/gnome-audio-proExecutableeforethe GNOME audio profile manager

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWgnome-media		   |
       +-----------------------------+-----------------------------+
       |Interface stability	     |External			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       Latest version of the GNOME Desktop User Guide for your platform.

       gnome-std-options(5), gnome-sound-recorder(1)

NOTES

       Written by Niall Power, Sun Microsystems Inc., 2004.

SunOS 5.10							    7 Sep 2004					gnome-audio-profiles-properties(1)