Abstract: Various communications clients such as, for example, Push to Talk over Cellular (“PoC”) client applications and PoC devices provided with client applications, provide extended services such as filler information for dead time intervals, and communication of PoC session content with non-PoC subscribers and with PoC subscribers who are offline. Through the use of one or more client applications to provide these extended services, the user experience is enriched and operators may monetize these extended services without need to modify the operating system or the network.

Abstract: A programmable memory device includes circuits that permit the selective disabling of certain functions when a battery supply voltage falls below the point necessary to sustain those functions while not disabling other functions of the device capable of working at the lower supply voltage. The programmable memory device includes a controller (422), programmable memory (426), and a voltage monitor (424), and is used in an application having additional circuitry (430). Power is furnished between the main voltage V.sub.CC terminal and the ground GND terminal from an external power source, typically a set of batteries. The voltage monitor enables full extension of the operational voltage range for specific functions of the programmable memory device, or for the application circuitry, or for both by reliably detecting the voltage level of the power source and providing an indication thereof.