[Asterisk-Users] very loud scratchy noise!

[Jesus chrisetopher]

Hello Group,
I am new to asterisk but learn a lot about it to this mailing list and
wiki currently i am facing problem about sip phone i have "PA 1688"
chipset ip-phone and i have iptel.org sip account i registered locally
and through iptel.org comfortably my problem is that when i called
from my sip phone to analog or any number after connection my sip
phone generates very load scartchy noise , i tried several settings of
DTMF but all in vein i enabled/disabled DTMF settings but not workin 
any info any hints any suggestions please ......

Thanks In Advance.
Jesus.