Universal ISDN/POTS splitter

A splitter for an ISDN/POTS telecommunication system, said splitter having first and second line terminals and first and second POTS/ISDN terminals, and comprising the cascade connection of a LC filter cell and a plurality of elliptical filter cells,

• said LC filter cell comprising a first symmetrical coil having a first winding with a first terminal connected to said first line terminal and with a second terminal coupled to said first POTS/ISDN terminal via said plurality of elliptical filter cells, and having a second winding with a first terminal connected to said second line terminal and with a second terminal coupled to said second POTS/ISDN terminal via said plurality of elliptical filter cells, said LC filter cell further comprising a first capacitor coupled between the second terminal of the first winding of said first symmetrical coil and the second terminal of the second winding of said first symmetrical coil,
• each elliptical filter cell of said plurality comprising a second symmetrical coil having a first winding with a first terminal coupled to the second terminal of the first winding of said LC filter cell and with a second terminal coupled to said first POTS/ISDN terminal and having a second winding with a first terminal coupled to the second terminal of the second winding of said LC filter cell and with a second terminal coupled to said second POTS/ISDN terminal, each elliptical filter cell further comprising a second capacitor coupled between the second terminal of the first winding of the second symmetrical coil of said elliptical filter cell and the second terminal of the second winding of said second symmetrical coil, a third capacitor connected across the first winding of said second symmetrical coil and a fourth capacitor connected across the second winding (L22b;
• L23b) of said second symmetrical coil,
• wherein said splitter comprises at least one RL circuit constituted by the parallel coupling of a resistor and a coil and connected in series with the second capacitor of an elliptical filter cell of said plurality of elliptical cells.