I tried to make this as thorough as possible. I have a 4p4c socket + cable here. As there is no manual for german wiring I had to measure each wire against each other wire while hearing the "ready to dial" tone to find it out, but I am still clueless.

This is what I got

• 12--0,4V-DC
• 13--4,2V-DC
• 14--208mV-DC
• 21-0.37V-DC
• 23-0V-AC
• 24-110mv-DC
• 31-395mv-DC
• 32-1mv-DC
• 34-221mv-DC
• 41-186mv-DC
• 42-5.7mv-AC
• 43--192mV-DC

Explaination:

• 1 means white
• 2 green
• 3 yellow
• 4 brown
• First number is one of the colors I put the mass of my oscilloscope to.
• Second number is the color/wire I put the signal of my oscilloscope to.
• one "-" is meant for separation
• Then the value follows
• Then the unit follows
• one "-" is meant for separation
• then there is the type of voltage/current measured

So for instance

43--192mV-DC means GND to brown, signal to yellow, result: -192mV, type of voltage/current measured: DC 

or

42-5.7mv-AC means GND to brown, signal to green, result: 5.7mV, type of voltage/current measured: AC 

Please tell me, which cable go to speaker and which to microphone. Also, do I need additional circuitry? In the english wikipedia there is a 500 ohms resistor. Do I need this, what is it for and where to put it?

I tried to make this as thorough as possible. I have a 4p4c socket + cable here. As there is no manual for german wiring I had to measure each wire against each other wire while hearing the "ready to dial" tone to find it out, but I am still clueless.

This is what I got

• 12--0.4V-DC
• 13--4.2V-DC
• 14--0.2V-DC
• 21-0.37V-DC
• 23-0V-AC
• 24-0.1V-DC
• 31-0.4V-DC
• 32-0.001V-DC
• 34-0.2V-DC
• 41-0.2V-DC
• 42-0V-DC
• 43--0.2V-DC

Explaination:

• 1 means white
• 2 green
• 3 yellow
• 4 brown
• First number is one of the colors I put the mass of my oscilloscope to.
• Second number is the color/wire I put the signal of my oscilloscope to.
• one "-" is meant for separation
• Then the value follows
• Then the unit follows
• one "-" is meant for separation
• then there is the type of voltage/current measured

So for instance

43--192mV-DC means GND to brown, signal to yellow, result: -192mV, type of voltage/current measured: DC 

or

42-5.7mv-AC means GND to brown, signal to green, result: 5.7mV, type of voltage/current measured: AC 

Please tell me, which cable go to speaker and which to microphone. Also, do I need additional circuitry? In the english wikipedia there is a 500 ohms resistor. Do I need this, what is it for and where to put it?