Conformance testing has a rich underlying theory popularly called IOCO-test theory. In the realm of IOCO-test theory, this paper addresses the issue of testing a component of an asynchronously communicating distributed system. Testing a system which communicates asynchronously (i.e., through some medium) with its environment is more difficult than testing a system which communicates synchronously (i.e., directly without any medium). What impedes asynchronous testing is that the actual behavior of the implementation under test (IUT) appears distorted and infinite to the tester. This impediment consequently renders the problem of generating a complete test suite, from the given specification of the IUT, infeasible. To this end, this paper contributes by proposing a tagging protocol which when implemented by the asynchronously communicating distributed system will make the problem of generating a complete test suite, from the specification of any of its component, feasible. Further, this paper describes how to generate the test suite from the given specification of the component.