Windows Mobile is a mobile operating systems developed by Microsoft for smartphones and Pocket PCs. Windows Mobile is the predecessor of Windows Phone.
Most versions of Windows Mobile have a set of standard features, such as multitasking and the ability to navigate a file system similar to that of Windows 9x and Windows NT, with support for many of the same file types. Windows Mobile also supported Internet Connection Sharing. Windows Mobile support virtual private networking (VPN) over PPTP protocol. Most devices with mobile connectivity include a Radio Interface Layer (RIL). RIL provides the system interface between the CellCore layer within the Windows Mobile OS and the radio protocol stack used by the wireless modem hardware.
The user interface has changed much between versions but the basic functionality has remained similar.
