Text and cell notification is just one of the methods used.
Depending on your situation, messages can be sent to your email and
landline phones. Alerts can include a recorded voice message sent to
your Voice Only Line Contacts. When you specify a voice only line, you
are requesting to receive any voice message included as part of a
Broadcast Alert to either a cell or landline. Whether a particular
Broadcast Alert includes a voice, text message, or email component is
determined by the sender of the Broadcast Alert. If you wish to
receive ONLY voice messages on a particular mobile device, add the
phone number to the list of Voice Only Line Contacts within
the MY ACCOUNT tab. When a mobile phone number is listed as
a Voice Only Line Contact, it will receive voice messages only.