Patent ID: 7912210
Filing Date: 2011-03-22
Classification: H04L,H04M

Abstract:
1. Circuitry adapted to interface between a telephone line and communications equipment, the circuitry comprising: an analog front end (AFE) circuit adapted to interface with the telephone line; a coder/decoder (codec) connected to the AFE circuit; interface circuit connected to the codec, the interface circuit comprising at least a first transformer having a first inductor electromagnetically coupled to a second inductor; and a digital circuit connected between the interface circuit and the communications equipment, wherein: the second inductor of the first transformer is connected to a second differential signal path connected to the digital circuit, such that the first transformer provides electrical isolation between the codec and the digital circuit, wherein the interface circuit further comprises a second filter connected to one of the first and second differential signal paths, wherein the second filter comprises: a first attenuation element connected to a first signal line of the connected differential signal path; and a second attenuation element connected to a second signal line of the connected differential signal path.