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Help reducing noise on IP phones

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phadobas

Technical User
Jul 30, 2005
612
US
Just got done setting up some IP phones that hang off of our SV8500. They are at a remote location, connecting to the system via vpn. They work great but they produce some (too strong) digital background noise under certain circumstances. The install is very fresh, and I only had a few minutes to play around with some test calls but this is what happens:

Our system is CCIS-connected to an old 2400ICS. When you call across this link, your speech travels via the VPN back to the headquarters building, to an IP PAD in the 8500, then CCIS over to the 2400ICS, then to the station. During moments of silence (no speech by either party), you hear a strong digital background noise (strong is relative, it's most obvious when you turn your volume up and nobody talks). It's stronger than any other combination of calling/called parties I've heard before. I'd imagine that some people would call it normal, yet, by the new users this was noticed immediately, and commented on. I need to reduce or eliminate this.

When you first pick up the IP phone, the dialtone is crystal clear. The phone is not picking up some electrical noise from nearby noise-sources. Unfortunately, I haven't had a chance to call different types of parties, like other IP phones at headquarters, so see if this shows up on IP-to-IP connections. I also haven't called other types, where the IP PAD would be part of the call, but not hitting the CCIS link, to determine if the noise is coming from the CCIS and/org the ICS2400. Hopefully I can determine that within 24 hours.

But anybody who has some advice, I would like to hear some of it.

When I worked with an Asterisk phone system in the past, our users thought many times that their call was disconnected, because that system completely silenced the line when nobody was talking. It was so unnatural for the users that I had to turn on a "Comfort noise" feature. I think in this case, this comfort noise is too loud...
 
IF you are using DT700's with the latest flash loaded, then you have audio/visual options within each phone. One option under audio is sidetone. This is in the perpherals book.
Main Menu
STEP 2:The Audio & Visual Settings Menu appears as follows:
Audio & Visual Settings Menu
Up Down Cancel
1.Network Settings
2.SIP Settings
3.Audio&Visual Settings
4.Maintenance Settings
5.Terminal Information

Sidetone Volume
On the Sidetone Volume parameter, set the volume of the side tone.
STEP 1: Select “1. Audio Settings” by pressing “1” key on the Audio & Visual Settings Menu.
Audio & Visual Settings Menu
STEP 2: Audio Settings Menu appears. Select “3. Sidetone Volume” by pressing “3”.
Audio Settings Menu
STEP 3:Specify the side tone volume [(lower) 0-7 (higher), 9 (Automatic)]. The default value is “9”.
Cancel OK
2.Default Data
1.Download Data
Exit
31.Audio Settings
2.Visual Settings
Up Down
311.Confirmation Tone
3.Sidetone Volume
4.Send Gain
5.Receive Bias
Exit
6.Receive Gain
7.Ring Settings
2.Music Select
8.RTP Alarm
9.DTMF Play Mode
 
Thank you for that belevedere. Yesterday I dived into the Peripherial manual myself, and I picked the noise-reduction option in the same menus you brought up in your post. That thing did wonders. I'm wondering what's the difference between the sidetone volume and the noise reduction setting?
 
I am not sure. Maybe side tone is an analog option and noise reduction is an IP option.
 
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