I have tried dialing 911 using my Sena SMH-10. Not sure of it is the phone or the Sena, but something in the circuit simply refuses to dial 911 without either physically typing in the number on the dialing pad or storing it in the Sena as one of the three speed-dial numbers (which lead to its own amusing series of incidents). It will NOT voice dial and my phone will not allow it to be stored as a contact.