voice calls quality

[zeinab.mahdavi]

Dear All,

we have a problem in voice quality ,

we use cisco as5350xm and use our special software as a PBX.

also there is a very heavy traffic of calls which are handled by operators. but the only problem is the noise in the calls. there isn't any echo and

also we have adjusted input gain and output attenuation with different values such as (+3,-3) (+6,-6)(+6,-14) and so on.

but the problem is remained. how we can remove the noise , which voice quality parameter decrease the noise ?

we also configure disable comfort-noise and all voip dial-peer are set to No VAD.

any suggestion will be appreciate.

[Jonathan Schulenberg]

Noise is an analog issue. Are the router ports FXS, FXO, or E&M? If not then there's nothing you can do on the router.

If they are analog ports you need to figure out where the noise is being injected. A butt set is the most common way: replace the router with the butt set and see if you hear the noise from either "side" of the router: ingress and egress.

While very unlikely if you don't hear the noise on either of the interfaces connected to the router but you do hear it when the call passes through the router it is possible there is a hardware failure in the VWIC/VIC or the PVDM. I had a DSP go bad once which resulted in hissing on the call. Again, rather unlikely.

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