Dial Tone Sound While Talking

[gmead7260]

Iwill be in the middle of a conversation and I will hear a dial tone like someone was leaning on their keypad and had accidentally pressed a button. But this is never the case. At first I thought it was some type of timer going off, but it never happens at the same time and there never seems to be any pattern to it. Sometimes I will hear it two or three times during my call. And I am the only one that hears it. The person I am talking to says they hear nothing at all.

Does ANYONE have an idea what it may be.

thanks,

Trailblazer