Perfect part, exactly according to specification

If you, however, like me, want to tap into a phone the American company Cisco in order, so you have to know the following: Cisco does not follow the standard, but also has headphones and micro swapped.

In general you have to be careful, because the Adapter alone does not make the success: This adapter is only for analog connections on the phone. In my Cisco which is a separate second connector on the bottom. So it does not work, simply plugs the phone off and then plug any headset (headphones + microphone) off. For what such a phone manufacturer for voltages etc. used to supply its own supplied handset is totally his thing. So beyond any standard.

My conclusion: If you know what you're doing, then this part is awesome. If you are not sure, just buy anyway and first try with a cheap headset.

Many phones incidentally is on the microphone contact a Phatomspannung. The Cisco 8945 there are 2V dc, the Nokia XpressMusic and C2 (both older models) are 1V DC. If you want to turn off the should in a microphone path solder a 0,1yF capacitor in series. But with most microphones is such a thing already included.