 Mobile PBX services also can include fixed-line phones.Mobile PBX systems are different from other hosted PBX systems that simply forward data or calls to mobile phones by allowing the mobile phone itself, through the use of buttons, keys and other input devices, to control PBX phone functions and to manage communications without having to call into the system first.A mobile PBX may exploit the functionality available in smartphones to run custom applications to implement the PBX specific functionality.