How to remove noise?

1. Brekeke Product Name and version: JTAPI 1.0.8

2. Java version: JDK 1.6

3. OS type and the version: Windows XP

4. UA (phone), gateway or other hardware/software involved:
X-lite, Asterisk

5. Select your network pattern from http://www.brekeke-sip.com/bbs/network/ ... terns.html :

6. Your problem:

When I record user's voice (uses X-lite)
There's no noise when I call my self
but if I make a call from another computer, there is loud noise.
How do I remove this noise?

Thanks

try reducing volume .

So far, I am able to reduce noise by using a lib which can deal with audio file. But I still have loud echo in the background.
Is there any way to remove the echo?
or this is the problem of microphone not the program itself.

Thanks

Let you use another microphone..

Which client software introduces the noise?

I used X-lite as the client software to make the call.
Can I solve echo problem by changing another micphone?
or
Is there any lib which is able to reduce echo?

Thanks

Actually, it's not a echo, it's a kind of noise always in the background. it's like cauesd when compressing audio file.
Can someone help?

how about network traffic?

Ya, I think network traffic is the reason to cause noise.
But I can't control network traffic.
So far, I have been able to remove two kinds of noise,
but if I use different computer to make a call, there is another kind of noise in the audio file.

are there any other heavy applications on the PC (both JTAPI's PC and client's PC..) ?
If so, they will consume the CPU power..