Abstract: The present invention relates to wireless communication systems and in particular to wireless communication systems which employ coder-decoder means in the transmission of information between two parts of the system. One aspect of the present invention provides method of setting up a wireless communications link between two radio stations which each communicate with a respective base station by the use of a selected one of several codecs; the method comprising: the signalling by each party to the other party of the codecs supported between each radio station and base station by said each party; and selecting an appropriate codec based upon the signalling information, whereby the quality of the link is maximised.