| 摘要 |
PURPOSE:To perform a tripartite call with balanced sound volume in the tripartite call including a central office, by amplifying the sound volume of the central office by using a multiplier, and amplifying a voice signal after converting it to a digital signal. CONSTITUTION:When the tripartite call among the central office lines 12 and 13, and an extension 14 is held, a time switch 3 sends sound data A and B from the central office lines 12 and 13 to the multipliers 8 and 7 respectively based on the information of a call control part 2, and amplifies them by multiplying them by a constant and sets them as sound data X and Y. The data X and Y are inputted again to the switch 3, and after time divisional switching being applied, are sent to an addition processing part 5. The processing part 5 replaces the data by the sound volume data in which the unbalancing in the sound volume is corrected, in such way that the data A is replaced by a data (Y+C), the data B by a data (C+X), and a data C by a data (X+Y), and they are sent to a time switch 4, and the time switch 4 sends a voice decoder to CODECs 1a-1c.
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