http://www.telekom.com/medien/medienmappen/Medienmappe+IP-Umstellung/260274 

tl; dr:

VoIP is nothing new and everyone knows Skype. BUT it is hard to use and doesn't work too well. So we invented this IP-based telephony.......

They just never stop to surprise me in so many, new and unpleasent ways time and time again... Way to go #DTAG!