nokia n91 call waiting alert

i have a n91 phone and for some reason the call waiting alert does not sound. i don't know where to se this setting. i can see another party calling in the screen display, but no alert tone. anyone have any ideas?
 
The call waiting setting is under the settings/call/call waiting directory. I checked on my N80, but there isn't anything that would disable or enable a tone. If you can see the alert on your screen but it isn't audible, I can't imagine what the problem could be. The only issue I have ever experienced with call waiting is it not working all together -
 
Back
Top