| 摘要 |
<p>The cassette is used as a linear equipment for connection in a two-wire line of two end telephones. It has simplified electrical circuitry and improved operational security in case of deteriorated insulation resistance along the telephone line or its connection to "earth". The cassette consits of two control units (10) 20) connected, on one hand, to the input-output terminals for a- and b-wires (31, 2) of telephone line (3) and to the contacts of relay (103, 203) of the control unit (10, 20), and on the other hand - to the first input-output terminal (11, 12), respectively, of duplex telephone subscriber (1, 2). The second input-output terminal (12, 22) is connected, respectively, to contacts of relay (10) 203) of the control unit (10, 20) and across diode (7, 8) in the direction to admission to "earth" (5). The diode in the control units (10, 20) is in the form of Zener diode (102, 202) and a light-emitting diode (LED) (101, 201) is connected in parallel to it. Each input-output terminal for the a- and b-wires (31) 32) of telephone line (3) is connected by varistor (4, 6), respectively, to "earth" (5). 1 claim, 1 figure</p> |
