A line unit interfaces voice band signals and wide band signals extending from D.C. into the voice band between an analog line and a digital telecommunication facility. The line unit includes an analog to digital converter, a control circuit for generating one of two control signals and a line circuit....http://www.google.fr/patents/US4232293?utm_source=gb-gplus-shareBrevet US4232293 - Line interface unit for voice and wide band signal coupling
Line interface unit for voice and wide band signal coupling
