When interacting within a closed timing domain the timing requirements (esp. setup/hold requirements) of all stateful elements (memory) in different systems or components can be safely met. Examples are a globally synchronous clock domain or an asynchronous handshake domain. Often it is, however, necessary to exchange signals between two (or more) such timing domains, as within a GALS system (globally asynchronous locally synchronous) each component/subsystem has its own timing domain. This exchange of data inevitably leads to metastability problems at the interfaces. To prevent or handle the problems with metastability of stateful elements at the interfaces of a system synchronizers are needed. In this work a survey of the different existing interfacing solutions of synchronous and asynchronous systems, including all levels of synchrony (mesochronous, plesiochronous, heterochronous, rational) and the different handshake-protocols (2-phase, 4-phase) of asynchronous system design shall be created. In the survey the interfacing solutions shall be compared according to criteria such as MTBF (Mean Time Between Failures), throughput, latency, assumptions on their functionality. From this a suitable and efficient solution shall be chosen for each possible system combination between synchronous and asynchronous systems, to further make a general reference book about interfacing solutions.