Abstract: A radio telephone capable of being operated in more than one radio telephone system, comprising communication means respectively associated with each of the more than one radio telephone system, monitoring means for monitoring signals of the more than one radio telephone system, and selection means responsive to said monitoring means for automatically selecting and re-selecting respective said communication means in accordance with the signals of one of the more than one radio telephone system fulfilling at least one predetermined criterion. The predetermined criterion can be based on a number of features such as received signal strength, access rights, system requests, least BER or frame error rate and user velocity.

Abstract: A radio telephone (200) is operable in a cordless telephone system or in a cellular telephone system. The telephone (200) incorporates circuitry to detect user velocity so that when the user travels more quickly the telephone automatically transfers from cordless mode, which is the preferred mode, to cellular mode. This prevents the degeneration in communication quality which frequently occurs when a user of a cordless system travels faster than walking pace.

Abstract: A radio telephone automatically hands over a call from one radio telephone system to another radio telephone system. Communication with respective radio telephone systems may be simultaneously continued during handover until the handover is complete, or communication with one radio telephone system ceases before communication with the other radio telephone system commences. Delays between signals of different radio telephone systems which would cause audible interference are inhibited by FIR filtering and/or dynamic time-warping. If an handover fails then communication with the original radio telephone system is restarted or continued.