ETHERLINK II - Repeater
Manual
Page 11 of 106
3
TECHNICAL DESCRIPTION
3.1
Application and general information about S-Access Etherlink_II devices
S-Access Etherlink_II devices represent xDSL modems (ITU-T G.991.2
– G.shdsl and ITU-T
G.991.2
– G.shdsl.bis standards, TC-PAM line encoding). They are designed to organize high-
speed data communication channels over symmetric digital subscriber lines (DSLs) with the
transmission rates from 200 to 5704 kbit/s (with the step of 64 kbit/s). The
TC-PAM
(
T
rellis
C
oded
P
ulse
A
mplitude
M
odulation) encoding used in these devices well combines such
characteristics as the transmission range, noise immunity and electromagnetic operability. The
number of levels (code states) in TC-PAM is increased up to 32 and a special error correction
mechanism is used. To increase the distance range by 2 or more times,
regenerators
can be
used.
The family of S-Access ETHERLINK_II includes devices with G.703 and Ethernet network
interfaces. Thus, the S-Access ETHERLINK_II equipment provides complex services which
allow one to transmit simultaneously voice and data as well as to construct TDM networks of
different topologies without using expensive interface converter, multiplexers and cross-connect
systems.
The devices of this family include network termination units (
N
TUs) and line termination units
(
L
TUs), which are installed at the customer (user) premises and the operator (provider)
premises, respectively. In addition, the devices of this family include regenerators. To organize
the “point-to-point” topology, the following schemes can be used: NTU – NTU, LTU – LTU or
NTU
–LTU.
The devices can be powered from local DC sources. Regenerators and NTUs can be fed both
locally or remotely from LTUs. Figure 1.1 presents an example of organization of data
transmission systems with the help of modems of the S-Access Etherlink_II family. Other
variants of the usage of this equipment are also possible.
О_ОП
