Nokia's first fully portable mobile phone after the Mobira Senator was the Mobira Cityman 900 in 1987. Nokia assisted in the development of the GSM mobile standard in the 1980s, and developed the first GSM network with Siemens, the predecessor to Nokia Siemens Network. The world's first GSM call was made by Finnish prime minister Harri Holkeri on 1 July 1991, using Nokia equipment on the 900 MHz band network built by Nokia and operated by Radiolinja. In November 1992, the Nokia 1011 launched, making it the first commercially available GSM mobile phone.