| 摘要 |
PURPOSE: A WLL(Wireless Local Loop) system for supporting a multipoint call service is provided to offer a multipoint voice call service through an RPC(Radio Port Controller) when interworking with a switch in which a multipoint call function is not supported by composing a voice mixer in the RPC. CONSTITUTION: An RPC has a voice mixer for mixing PCM(Pulse Code Modulation) voice data transmitted from an RP(Radio Port) through two or more channels for a simultaneous call service among two or more subscriber terminals, and outputs the mixed PCM voice data to a switch. The voice mixer has a PCM decoder for converting the received PCM voice data into linear PCM data by a sample unit, and a digital adder(42) for mixing 16-bit linear PCM data inputted from a plurality of channels and outputting the mixed 16-bit linear PCM data. The voice mixer has a PCM coder(43) for converting the linear PCM data outputted from the digital adder(42) into PCM voice data suitable for transmission.
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