| 摘要 |
A description is given of a duplex device comprising two symmetrical circuits interposed between the telephone line A, B and two users A1, B1; A2, B2 and incorporating means for cutting off one of the two users when the other is connected to the telephone line. According to the invention, each of the said circuits C1, C2 comprises two meshes 1, 20, the first 1 of which contains a capacitive element 3 and resistive elements 7, 8 in parallel with the said capacitive element, and the second 20 of which contains an inductive element 22 acting as a relay and a capacitive element 24 in parallel with the said inductive element 22; means 26 are also provided for connecting the second mesh in parallel with the first mesh according to the voltage drop in the resistive branch 5 of the said first mesh 1. (Fig. 1) <IMAGE> |
