How can previous licenses of Microsoft System Center 2012 be converted to version 2012? And what is the ratio used for the transition?

The transition from older System Center server and client management licenses to version 2012 is possible only if they are covered by active Software Assurance. In such case the following table provides the conversion ratios that apply.

For server components:

For client components:

For client components:

Source: Licensing Datasheet_Microsoft_System Center 2012 English as is 2017-03-06