Patent ID: 8228940

Claim:
A Voice over Internet protocol (VoIP) device, comprising a time division multiplexing (TDM) bus, a plurality of digital signal processors (DSPs), a plurality of subscriber line interface circuits (SLICs), a processor, a memory, and one or more programs, wherein the SLICs are respectively connected to a corresponding plurality of telephones, wherein the one or more programs are stored in the memory and operable to be executed by the processor and operable to prevent noise generation of the VoIP device, the programs comprising: a timeslot allocating module operable to distribute the TDM bus to a plurality of calling timeslots and a special timeslot, and to allocate at least one of the calling timeslots to each of the SLICs; a processor controlling module operable to select one of the DSPs as a special DSP and direct the special DSP to generate an alternating voltage signal to the special timeslot, wherein the processor controlling module connects an output end of the special DSP to the special timeslot and directs the special DSP to continuously output the alternating voltage signal to the special timeslot; and a subscriber line controlling module operable to direct the SLICs to receive the alternating voltage signal from the special DSP by use of the special timeslot so as to substantially reduce noise generation of the VoIP device, wherein the subscriber line controlling module connects an input end of the SLIC to the special timeslot and loop the TDM bus to direct the SLIC to receive the alternating voltage signal from the special DSP by the special timeslot upon the condition that the telephone corresponding to the SLIC is disengaged; wherein the subscriber line controlling module directs one of the SLICs to process a call related to one of the telephones by use of the allocated calling timeslot upon the condition that the one SLIC detects that the corresponding telephone thereto starts the call, and directs the one SLIC to receive the alternating voltage signal from the special DSP by the special timeslot upon the condition that the one SLIC detects that the corresponding telephone finishes the call.