Patent ID: 7149305

Claim:
A combined sidetone and hybrid balance apparatus comprising: at least one filter, the at least one filter having an input and an output, wherein the at least one filter uses a first predetermined set of filter coefficients in a first mode of operation, and a second predetermined set of filter coefficients in a second mode of operation; a combiner having at least a first input and a second input, the second input coupled to the output of the at least one filter, the combiner for combining the at least a first input and a second input to produce an output; a first switch coupling a first input signal to the first input of the combiner in the first mode of operation, and coupling a second input signal to the first input of the combiner in the second mode of operation; a second switch coupling the output of the combiner to a first output in the first mode of operation, and coupling the input of the at least one filter to the first output in the second mode of operation; a third switch coupling the second input signal to the input of the at least one filter in the first mode of operation, and coupling the first input signal to the input of the at least one filter in the second mode of operation; and a fourth switch coupling the input of the at least one filter to a second output in the first mode of operation, and coupling the output of the combiner to the second output in the second mode of operation.