Q. Explain about Hybrid network?

Hybrid network (sometimes known as a hybrid coilor duplex coil) in a telephone set is a special balanced transformer used to convert a two-wire circuit(the local loop) in to a four wire circuit(the telephone set) and vice-versa, hence enabling full duplex operation over a two wirecircuit. Essentially, hybrid network separates transmitted signals from received signals. Outgoing voice signals are typically in 1-V to 2-V range, whereas incoming voice signals are typically half that value. Another function of hybrid network is to allow a small portion of transmit signal to be returned to the receiver in the form of a sidetone. In sufficient sidetone causes speaker to raise his voice, making telephone conversation seem unnatural. Too much side tone causes speaker to talk too softly, thus reducing the volume that listener receives.