A system and method for transparently transmitting aural signals across a
wide area network (WAN). The system of present invention is connected to
one or more of a private branch exchange, a key telephone system, a
telephone, a facsimile machine, and a modem, for example. In the case of
voice transmission, a user places a telephone call using the same
procedure that is used when placing a telephone call over a conventional
public switched network. The aural signals are translated into a format
that is compatible with the local area network (LAN) and the translated
signals are transmitted to a router or a switch that connects the LAN to
the WAN. The data is transmitted across the WAN to a router or switch
coupled to a second LAN. The data is then sent to a destination central
site unit or PC which translates the signal into a format that is
compatible with the telephone system connected thereto. The present
invention provides a voice quality that approaches, equals, or exceeds the
voice quality of conventional telephone switched networks. This high voice
quality is achieved by utilizing a high quality voice digitization
algorithm, by ensuring a low maximum network delay, by dynamically
compensating for variations in network delay, and by using a forward error
correction technique that can recreate lost or delayed signals in a manner
that recreates the signal so the lost signal is typically not detectable
by a user.