Wireless transmission is an interesting alternative or supplement to the wired one. An interesting problem is the cooperation between wired and wireless networks. The simplest way is to do a conversion on a physical layer level, however, there are many conditions that are hard to fulfil in order to achieve proper co-operation between both links. It is also possible to do a conversion on a link layer level. It has many advantages obtained at the cost of additional transmission delays. The protocol converter may have several hardware and software variant that are discussed. A basic time analysis is shown to present the converter?s influence upon network behaviour in different situations.