These keys are easily interchanged using enharmonic equivalents. The diphthongs and may be interchanged since is an allophone of in final syllables. Similarly data can be interchanged between the codes written in these languages in both ways. Note that notation varies, so and may be interchanged in different texts. Several streetcar lines and interurban railways interchanged passengers in Georgetown. Keep this in mind as nomenclature is often interchanged. The terms are frequently interchanged in the literature. Because no standard exists, IVUS catheters cannot be interchanged between different manufacturers. The tuning pegs and the nut were replaced, the latter interchanged a number of times. The two astronauts specially fitted seatliners were interchanged. In flat pack systems, many components can be interchanged. Tools and punches can be interchanged for different part requirements. The simplest operation is conversion where the subject and predicate terms are interchanged. However, "den" cannot be freely interchanged with "so". Almost all parts, including screws cannot be interchanged with the Japanese Type 38.