PVDM for Analog Calls

controlcontrol Member Posts: 309
If I'm making calls in a lab environment between 2 analog devices connected to separate FXS ports, is there a need for for PVDM modules in my router? What If I extended my setup to Analog to IP Phone?


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    azaghulazaghul Member Posts: 569 ■■■■□□□□□□
    It depends...

    If they are installed in an NM module, or are in one of the EVM/HDA module, then the PVDMs are usually installed on the module to support FXO/FXS. This is usually for older 2600/3700 series routers as they don't natively support FXO/FXS.

    If they are installed in a VIC/HWIC slot, then you are going to need PVDMs installed in the router to perform the Analogue-Digital conversion. This is for the newer 2800/3800 series and later, but also the old 1750/51/60 which accept VIC/WVICs natively.

    On a single router it would be...

    analogue phone -> FXS port -> DSP (A-D) -> DSP (D-A) -> FXS port -> analogue phone
    analogue phone -> FXS port -> DSP (A-D) -> IP phone (D-A)

    The IP phones have DSPs built in to do the final digital-analogue conversion.
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