First of all, the Applet-phone is a SIP User-Agent
with audio and text messaging capabilities. But i s also embedded in
an applet where you can use it as usual if your firewall allow you to
use the UDP transport. If not, you can use TCP to carry your voice in a
voice messaging fashion. Your voice is recorded and encoded locally
then sent as a message, decoded and played back by your peer. Voice
messaging allow you to go through any firewall, so that you can
continue to chat and talk with your friends from an applet !
