All driver-generated fields in the message header are in Unicode. Strings that the driver receives, however, are passed in the same format as received. If you have set the appropriate registry keys, the message body is converted to Unicode by MSDefault using carrier-supplied DLLs. The key is HKEY_LOCAL_MACHINE\Software\Microsoft\WIS\Control and its values are CONVTRDLL and CONVTRPARAM. You may set CONVTRDLL to the name of a DLL that performs the conversion, or to the string "BUILTIN". If you use "BUILTIN", the default Unicode conversion routine in MSDefault is used. You may set CONVTRPARAM to A2U to convert from ASCII to Unicode, or to U2U to indicate that no conversion is required.
You can set the subkeys so that conversions are done differently on certain devices or addresses. For example, by setting the key HKEY_LOCAL_MACHINE\Software\Microsoft\WIS\Control\Device1, you can specify which DLL and conversion is used on messages arriving on Device 1. The following registry key example shows how to convert incoming messages on Addr1 of Device 1 from ASCII to Unicode, using the built-in conversion routine.
HKEY_LOCAL_MACHINE\Software\Microsoft\WIS\Control\Device1\Addr1
"ConvtrDll"="BuiltIn";
"ConvtrParam"="A2U";
The Radiotest test utility, Radiotest.exe, also supports Unicode messages. For more information, see Sending Test Messages with Radiotest.