Devices are able to identify other devices in a shared audio space by emitting a signal and receiving messages from other devices over a data connection indicating which of the other devices received the emitted signal. The antenna can be movably coupled to a housing such that the antenna can float andor move freely with respect to the housing. The portable telephone stores data regarding frequency of key determination made by the user in the past when the plurality of keys was depressed at the same time, with regard to a combination of these keys.