I am running Call Manager version 6.1(2) with some 5000 IP Phones registered to this. All the endpoints are 7940 phones.
Whenever I pickup a receiver, along with the dial tone , I am getting a background noise also. If the volume of the phone is increased, it gets worse. This happend only for the dial tone. When users start pressing the digits, this noise doesn't exist. And this happens for almost 50% of the phones.
I have some IP communicators also. But these phones doesn't have any problem.
Has anybody come across the same problem.