Patent ID: 7689233

Claim:
A telephone system, comprising: a base unit; and at least one cordless handset wirelessly communicable with the base unit, wherein the base unit comprises analog half-duplex switching speakerphone circuitry for providing a handsfree operation for the at least one cordless handset, and wherein the analog half-duplex switching speakerphone circuitry detects signal levels input/output from the at least one cordless handset to determine a communication mode, wherein the base unit comprises a hybrid circuitry coupled with a PSTN to receive/transmit audio signals from/to the PSTN and a RF modular for demodulating audio signals received from the at least one cordless handset and modulating audio signals received from the hybrid circuitry, wherein the analog half-duplex switching speakerphone circuitry is between the hybrid circuitry and the RF modular, and wherein the analog half-duplex switching speakerphone circuitry further comprises: a first comparator for comparing a receive level and a transmit level at the RF modular side of the analog half-duplex switching speakerphone circuitry; a second comparator for comparing a receive level and a transmit level at the hybrid circuitry side of the analog half-duplex switching speakerphone circuitry; and a controller for determining an operation mode of the telephone system based on outputs of the first and second comparators.