How do I enable call waiting notification when I am calling another person? When I used my previous phone, when I am calling someone, I used to get a notification if the party that I am calling is in another call and I am waiting. I usually don't like to disturb people when they are in another call so I promptly hang up. But I've noticed that my HTC Desire S does not tell me that information. 

Is it by design ? 

Is there anyway I can enable this feature? 

An app perhaps? 

Or are all the phones running Android have this feature turned off ?

Just to clarify, I am NOT looking for activating call waiting on my phone so I get an alert when another person is calling me. I want to know when a call I initiated is in call-waiting on the other end.
Unfortunately, most (maybe all) of the Android phones don't have this option. Check this issue: http://code.google.com/p/android/issues/detail?id=7048