Radio Interface Layer

The RIL enables wireless voice or data applications to communicate with a GSM/GPRS or CDMA2000 1X modem on a Windows Mobile device.

The 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.

Except for PPP connections, all interaction between the Windows Mobile OS and the device radio stack is via the RIL.

In essence, the RIL accepts and converts all direct service requests from the upper layers (i.e., TAPI) into commands supported and understood by the modem.

Instead, the final link to the modem is typically the standard serial driver provided by the OEM's platform.