German phone giant Deutsche Telekom said on Friday that it would take a 25 per cent stake in a cellular phone venture in China that is being set up with Siemens, AIG Invest and the China International Trust and Investment Corporation. The network will be based on Europe's Global System for Mobile communications(GSM) and will cover the cities Tianjin, Wuhan and Qingdao, which have a combined population of more than 20 million inhabitants.