| 摘要 |
FIELD: telephone equipment. SUBSTANCE: device is connected in series with telephone set to voltage clipping telephone line which provides power supply of device elements. In addition device has counter which counts pulse packets in order to measure talks only with specific called parties. Goal of invention is achieved by introduced called number decoder, timer, and OR gate. EFFECT: increased reliability, increased functional capabilities, possibility to plug device into arbitrary location of telephone line and to serve several parallel telephone sets. 4 cl, 2 dwg
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