Translated into virtual network within the specific GSM calling extension number special number, and select 2 m digital trunking will call mobile access pass GMSC, GMSC again to the calling and called the call information for intelligent network platform service switching points of SSP, triggered by the SSP to service control point SCP, thus realizing the integration of wired and wireless.Not only convenient for the user to achieve the PBX switches extension mobile virtual network number and phone call group, group clients will phone bundled with internal switches on, a stable group big clients, and the development of mobile phone users, but also maximize the save the enterprise communication fee and phone, mobile phone users and mobile company created the economic and social benefits, also for 2 m broadband data services and other value-added services integrated access laid a foundation.