Headphone jack & audio switching

[ab1jx]

This turns it off but it stays off when you unplug the headphones:

Code:

amixer -c0 cset numid=28 0

numid=28,iface=MIXER,name='Speaker Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=off

So you could script turning it on and off but at least you get privacy.

For manual control a couple quick scripts.  Headphones stay on until you unplug them. 
Create them with your favorite editor someplace in your path, sudo may be required:

Code:

cat spon
#!/bin/bash
# Turn laptop speakers (always card 0) on
amixer -q -c0 cset numid=28 on &> /dev/null

cat spoff
!/bin/bash
# Turn laptop speakers (always card 0) off
amixer -q -c0 cset numid=28 0 &> /dev/null

chmod +x sp*

Alsamixer reads the state of the speaker switch but can't change it.  amixer is in alsa-utils.

Until somebody moves it here's a linked image to a block diagram.  Datasheets are easy to find by searching.