Controlling VOIP interfaces on Windows Mobile devices

RTC 1.5 can be restricted to use only certain types of interfaces (Wifi, Ethernet, etc.) on Windows Mobile devices. Same restriction cannot be applied on Windows CE, as RTC uses connection manager functionality to do that, which is not available on Windows CE.

RTC can be restricted using the following reg keys. These reg keys need to be set before RTC gets initialized.

HKLM\Comm\RTC\AdapterTypes

One can list all the allowed interfaces as numerical keys:

e.g. 1

              2

              3

              ETC.

The value of each key should be an ORed value of the connection manager interface type and sub-type

e.g. If one wants to allow Ethernet interface only.

The connection manager interface type to use will be CM_CONNTYPE_NIC (0x2)

The connection manager sub-interface type to use will be CM_CONNSUBTYPE_NIC_ETHERNET (0x1)

The Ored value = (0x2 << 16) | 0x1 = 0x20001

So the reg key will look like:

HKLM\Comm\RTC\AdapterTypes\1 (DWORD with value 0x2001)

Similarly, if Wifi is also desired,

The connection manager interface type to use will be CM_CONNTYPE_NIC (0x2)

The connection manager sub-interface type to use will be CM_CONNSUBTYPE_NIC_WIFI (0x2)

The ored value = 0x2 << 16 | 0x2 = 0x20002

So the reg keys will look like:

HKLM\Comm\RTC\AdapterTypes\1 (DWORD with value 0x2001) ß for Ethernet

                                                                 2(DWORD with value 0x2002) ß For Wifi