VCS VideoJet G.703, Manual, Page: 16 / 90

Introduction
18
VideoJet X.21/G.703
Manual
X.21/G.703 Transmission Concept
Until now, video and audio signals have been transmitted along
dedicated lines, e.g. coaxial cable. To make use of existing digital
networks and the simpler installation that entails, devices are
required to convert broadband analog video and audio signals for
existing transmission lines. The main advantage clearly lies in the
virtually unlimited loss-free transmission distance between sender
and receiver. The digitized video live image is transmitted across an
X.21/G.703 transmission line with the
VideoJet X.21/G.703
.
Fig. 2-1
VideoJet X.21/G.703
Concept
The
VideoJet X.21/G.703
transmission system was designed,
to enable multimedia data streams over an existing X.21/G.703
leased line. It combines state-of-the art compression technology
with ease-of-use, enabling you to transmit full colour live video with
accompanying full-duplex audio and data over a X.21/G.703 leased
line.
The
VideoJet X.21/G.703
functions as a DTE (data terminal
equipment). An adapter used as the line termination for the X.21/
G.703 leased line must therefore be used as the DCE (data circuit
terminating equipment).
The X.21 port of the
VideoJet X.21
is directly connected to this
termination. The transmission rate matches the clock output by the
DCE (data circuit-terminating equipment). It can be anything from
64 Kbit/s to 2.048 Mbit/s (x times 64 Kbit/s, where x must not be
greater than 32).
DTE
VideoJet
XE
Monitor
Receiver
VideoJet
XS
DCE
Sender
X.21/G.703
Transmission Line
DCE
DTE
Transmitter