Is the support for the users of cell phones, allows dialing 911, a standard number for requesting help in situations of emergency. One can also take into account that cell users are mobile; the system allows the emergency services to find your location.
Citel PBXgateways are installed at the central PBX location, and EXTenders are deployed at branch offices, call centers, or at home offices over managed IP connections, DSL, cable, or analog circuits