Configurations
of GSM/VoIP networks allow the service providers to avoid the local Wired
Public Switched Network (PSTN) in communication with a GMS mobile handset. As a
result, the high rates charged by telephone companies are avoided.
Integration of the phone set (cell or land line) into the company phone system. For instance, if it is impossible to find a person by the office phone, then with the help of the integrated cell phone one can set a call redirection to a cell or another telephone number, in case if that telephone is also unavailable the call will be redirected to a voice mail.