How to fix SPA3102 PSTN LINE crackling/hissing?

[paulsmrcka]

Hi,

I use the SPA3102. Incoming calls come in via the PSTN line and outgoing calls leave via the internet. Out going calls, I have no problems. With the incoming calls I get a crackling/hissing line. I've checked my PSTN Line without the SPA3102 and it is clear as one would expect. Could you advise a possible solution to the crackling sound.

I have attached my PSTN Line settings for reference.

Cheers

Paul

[Daniele Giordano]

Crackling is an irregular form of very light static, similar to       the sound a fire makes.

A common cause is poor electrical connections, in particular poor       cable connections. Other causes are electrical interference and a defective       power supply on the phone.

Use a two wire telephone cable (tip and ring only), check your impedance value and decrese gain level.

Hissing is more driven and constant than static. White noise is       a term often associated with strong hissing. Pink noise is a less constant       hissing noise and brown noise even less constant still.

A common cause of hissing is VAD.

Try to fix jitter buffer and increase its value.

This is an helpfull link: http://www.cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00801545e4.shtml

Regards.