Just going through my "optional" list on the 777 and I do not see any reference to aural alerts in the Warning section that talks to the Altitude Alerter. EICAS messages, and highlighted amber boxes around the altitude looks to be the normal functionality with no others offered. Having said that you would be absoultely amazed at all the different configurations possible when the customer sits down and checks off his idea of the perfect 777
. Don't bet a dime on my answer to your question.
The system you describe without the aural alert is refered to as the "basic 900' alert and 200' deviation" so that would lead one to believe that there are other versions out there but I do not see them.