T-Mobile have had great success in merging their network with manufacturing handsets as well. The mobile phones are likely to be initially locked to the T-Mobile network, but using them on other networks is also a possibility for those who want to, simply by using an unlock code. Some of the most notable T-Mobile handsets are the Rapport and Vivacity. T-Mobile originally started life at Mercury One2One but have since gone on to merger with Orange with aims to become the world's largest network.