The problem is that when one extension is on a call, another extension (or external caller) calling to it doesn't hear the call waiting sound (fast ringtone) but a normal ringback sound (as if the extension wasn't on call). To put it in simple words - if extension A and B are on a call, a call from extension C to either A or B results in extension C hearing a normal ringback sound instead of a call waiting sound. File indications.conf has needed parameter for this callwaiting = 414/100,0/100,414/100,0/100,414/600,0/3000 but looks like system not using it. Any help? It's really important. Thanks.