MAS.632 Conversational Computer Systems - MIT OpenCourseWare

Ethernet
Workstation Etherphone
Workstation
Voice Manager
Voice File Server
Voice Control
Server
Figure 11.1. Etherphone architecture. (Figure (From by Terry MIT OpenCourseWare
and Swinehart,
, after "Managing System." Terry and Reprinted Stored Swinehart, Voice with 1988.)
in per- the Etherphone
Systems mission 01988, from ACM.) Tkansmctions on Computer
included hardware to digitize voice and control analog telephone lines, both
under the control of a workstation in concert with various networked servers. The
project included call control applications, integration of audio with the local com-
puting environment and its associated user interfaces, and voice-oriented appli-
cations such as audio editing, voice annotation of text, and scripted docurnent~.~
The Etherphone itself was a hardware device, capable of digitizing and playing
back speech over an Ethernet. Its physical components included a speaker, rnicro-
phone, and a telephone handset, as well as a standard analog telephone line
interface, which enabled calls to be placed over the external telephone network.
Internal "calIsn were transmitted over the Ethernet. During call setup, a central-
ized call control server negotiated with the user's workstation and then sent com-
mands to an Etherphone agent, which dealt with the physical devices in the
Etherphone and the stream of audio data packets. Voice was transmitted over the
Ethernet either between Etherphones or between an Etherphone and a variety of
servers as shown in Figure 11.1. The servers included a storage server to save or
retrieve sound from disk, and a text-to-speech server that received text and trans-
mitted the synthesized speech over the network.
Internal and external call processing proceeded differently within the Ether-
phone environment. In the case of an internal call between Etherphones, the
entire conversation was transmitted over the Ethernet and local distributed pro-
'See previous discussion of scripted documents in Chapter 4.
Etherphone