Abstract: A portable cellular telephone comprising a main body for housing at least a microcontroller, a display screen, an audio receiver and a microphone. An extendible section that houses a number of function keys such as the standard telephone keys, slides out of the main body to expose the display screen in its entirety. The extendible section also includes LED's to back light the keys when desirable. The electrical connections between the extendible section and the main body are achieved through wiper contacts in the main body that slide over conductive strips on the under surface of the extendible section. The keys in the extendible section are each connected to resistors of different values, these resistor/key combinations are all connected in parallel to two conductive strips. A resistor bridge is formed by connecting a resistor in the main body to the resistor key combinations.

Abstract: A communications system having a pre-defined calling group with a plurality of members is disclosed. A plurality of personal communication devices (PCDs) each have a system ID and a group ID, and each member of the group is assigned one of the PCDs. The system ID and the group ID both have a predetermined characteristic, where each system ID has a first variation thereof and each group ID has a second variation. A first group member having a first PCD contacts a second member having a second PCD by entering into the first PCD the second PCD group ID. The first PCD transmits the first PCD system ID and the second PCD group ID to a communications switch. Based on the first PCD system ID, the communications switch locates a record for the first PCD in a switch database and determines therefrom that the first PCD can contact the second PCD by way of the second PCD group ID. A group database in switchable communication with the communications switch has the system ID and group ID for each group member PCD.

Abstract: Methods of and corresponding apparatus for scheduling messages on an operating channel (123) in a selective messaging system (100) for a selective messaging unit (135) include choosing a preferred channel (711) from a first channel and a second channel, setting a first priority for the first channel (713) and a second priority for the second channel, the priorities, for example by relative magnitude, corresponding to the preferred channel, and scheduling a message (715) for the selective messaging unit on the preferred channel. Analogously, at the selective messaging unit a method of selecting an operating channel includes detecting a first priority signal corresponding to the first channel (621) and a second priority signal corresponding to the second channel, and based on a comparison of the priority signals (623) selecting the operating channel (625) from the first and second channel.

Abstract: In a selective radio paging receiver, power supply for a local oscillator portion which has the longest period to take up to normal operation from on-set of power supply is performed with an elevated voltage higher than the battery voltage in the normal operation to shorten the take-up period. Subsequently, the battery voltage is supplied to the local oscillator portion together with the radio reception portion, wave shaper circuit and so forth. Therefore, power supply for the radio reception portion and the wave shaper circuit can be delayed to shorten the overall power supply period to improve battery saving effect.

Abstract: In a communication system for transmitting and receiving burst signal between a round-trip satellite and a ground station, upon transmission of a transmitting burst signal from the round-trip satellite, a standard time upon transmission is added to the transmitting burst signal. In the ground station, the time data added to the transmitting burst data is extracted and compared with the standard time upon reception to derive a transmission delay period. A transmission timing of a burst signal to be transmitted from the own station is controlled depending upon the transmission delay period. By this, even when a distance between the ground station and the round-trip satellite is varied, overlapping of the burst signals in the time slots on the same time axis can be successfully avoided. Also, a guard time can be shortened to contribute for improvement of the transmission efficiency.