You can administer up to four Extended Access applications on one telephone. Extended Access applications include Extension to Cellular, Cellular Service Provider (CSP), Service Provider Fixed-Mobile Convergence (SPFMC), SIP, and Public Fixed Mobility (PBFMC) PBFMC and Private Fixed Mobility PVFMC. You can also administer more than one instance of an application on one telephone. For example, you can map one office telephone to two different cell phones through Extension to Cellular.