Abstract: A radio transceiver unit for use in a radio communications system and operable in a direct mode of operation (DMO), the radio transceiver unit comprising:

Abstract: A method by which a plurality of users share access to a resource such as a common communications channel. Each user is assigned a priority and is provided with a non-uniform probability distribution function corresponding to that priority, with the sum of the several non-uniform probability distribution functions being uniform. Whenever a user wishes to access the resource, the user selects a random number according to its non-uniform probability distribution function and computes an access time based on the selected random number.

Abstract: In a speech processing system (10) characterized by a finite range of audio levels, the speech processing system (10) receiving an incoming audio signal, the speech processing system amplifying (12) the incoming audio signal by an audio gain factor, the speech processing system (10) representing the amplified audio signal by the finite range of audio levels, a method for adjusting the audio gain factor, including the steps of: decreasing the audio gain factor when detecting clipping of the amplified audio signal, maintaining the audio gain factor for a hold time period, and increasing the gain factor when detecting that the result of amplification of the incoming sound levels by the audio gain factor, is lower than the highest level of the finite range of audio levels.

Abstract: A communication method is provided in which mobiles operating in a trunk mode operation transmit a message on a direct mode operation channel indicating a trunk mode operation connection is present. If a mobile outside the range of coverage of the trunking system receives the message it will deduce from the message the slot structure of the trunk mode channel and its timing, and will then be able to transmit a request for a direct mode connection on an appropriate slot of the trunk mode channel. Some or all of the mobiles operating in trunk mode will then be able to switch to direct mode to connect with the mobile outside the range of coverage.