Abstract: A system and method for extracting a data signal transmitted by a signal source encoding the data signal onto first and second binary signals as a known two-bit binary state of the two signals taken together includes memory storing single bit binary patterns representative of known bit pattern and a reference table of two bit binary state couples representative of a data signal bit encoded onto the first and second binary signals. A processor monitors one of the first or second binary signals and compares the one monitored binary signal to the stored single bit binary patterns in memory. The processor stores, if a match is found, the respective binary states of the first and second binary signals in memory as a pair of two bit binary states.

Abstract: An apparatus for use with cellular telephone to indicate an incoming telephone call to a user includes a cellular telephone battery pack having a circuit that generates a voltage signal with a value representative of the current being drawn from the battery by the operation of the cellular telephone. A status determination circuit monitors the voltage signal and generates a powered up state signal whenever the value of the voltage signal increases from a first selected lower value to a first selected higher value for a first preselected period of time. An incoming call detection circuit whenever the powered up state signal is present and either the voltage signal is representative of a selected periodic current transient in the current being drawn by the cellular telephone for a second preselected period of time. An alarm is operative upon receipt of the alarm start signal for indicating an incoming call to a user.