Abstract: A method to notify an operating system level application includes setting a value (while executing in the system management mode) that is visible to the operating system level application before returning control to the operating system. The operating system visible value may cause an interrupt service routine to execute. The interrupt service routine may determine various characteristics of the system management event and pass this information to the operating system and/or application.

Abstract: Techniques to notify an operating system level application that a system management event has occurred include setting a value (while executing in the system management mode) that is visible to the operating system (and applications executing thereunder) before returning control to the operating system. The operating system visible value may cause a special system management driver routine to execute. The special system management driver routine may determine various characteristics of the system management event and pass this information to an application.

Abstract: A cellular telephone includes a receiver for receiving cellular communications and a transmitter for transmitting cellular communications. A controller is coupled to the receiver and the transmitter and controls the receiver and the transmitter based on the command signals. The controller includes a first memory for storing call rate information indicative of rates charged for the cellular communications. A timer provides a timer signal indicative of a time during which the cellular communications take place. The controller determines the amount of currency to be charged for the cellular communications based on the call rate information and the timer signal. An administrator station is provided for loading a threshold amount of currency into the cellular telephone. The entire system can be tracked and managed, and system wide statistics are available to the system operator.