Universal channel unit switchable between two wire and four wire configurations

摘要: The universal channel unit includes a interface circuit that uses pair of fixed ratio transformers to terminate both two wire and four analog transmission facilities on selectable basis. also plurality signalling circuits, each which is switchably connectable via the provide DC match format required by associated facility. circuits include: DX, FXO, FXS, other circuits. AC component signals carried facility output an adaptive impedance balance functions closely minimize signal reflections under control microprocessor. This network connected PCM echo canceller as well equalization gain