Noise on the Line

[jms]

This is the current set-up

1x UC320W v2.0.9 (3)

1x ESW-520-8 v2.1.19

8x 508G Phones

3x FXO lines from a standard telecom provider no VOIP

When people are making and receiving calles they don't come in clear. I can confirm that on a few occasions I called in and when listening to the Voice Prompts of the auto attendant I could hear the static/cracks

I have done the FXO impedance matching

Checked that the line's were not inversed (polarity)

DSL comes in on the first FXO port and it has been properly filtered, I have disconnected it then reconnected it and did notice anything related to it, somethime it would do the sound when it was and even when it wasn't connected

What else is there to check or look into?

[Christopher Edgeworth]

Hi,

Have you tried connecting an analog phone to the FXO lines to see if you hear the problem on the analog phone?

Check to make sure there isn't anything plugged into the same electrical circuit as your PoE switch that might cause electrical noise (motor, microwave, etc).  -- UPS will clean up the power.

Does the volume sound particularly loud?  Have you tried reducing the FXO gain settings? 

Do both sides (PSTN user and IP phone user) hear static or just one side?

Chris

[jms]

Have you tried connecting an analog phone to the FXO lines to see if you hear the problem on the analog phone?

-Yes with analogue phone connected directly to line the sound is fine.

Check  to make sure there isn't anything plugged into the same electrical  circuit as your PoE switch that might cause electrical noise (motor,  microwave, etc).  -- UPS will clean up the power.

-Yes it is connected to a UPS

Does the volume sound particularly loud?

-No it sounds normal

Have you tried reducing the FXO gain settings?

-No for I am not sure what that does, I understood it was if the volume was to loud or not loud enough. Can you descibe to me what it does and how it affects the line.

Do both sides (PSTN user and IP phone user) hear static or just one side?

-Yes both sides.

[nalbert]

jms,

It is highly unlikely that Static and crackling are created in IP networks. They are more likely in Analog circuits. I would ask the phone users the following

- Does it happen on all Phones or just a few phones. Any paterns there.

- Does it happen on all Lines or just 1 or more lines (You might have to configure a Shared FXO to find out which line is being used)

After you acertain this, if you isolate the problem to a lines. I would then track the lines back to see where there could be possible interference. If it is a phone then I would open up a TAC case.

Navin