Technical data

www.westermo.com Theoretical and general applications 71
Tomorrow’s highways
Intensive work is in progress to create interna-
tional standards and affect the expansion of what
is known as tomorrow’s highways for communi-
cation. Fast digital high-speed networks, such as
broadband, that can transfer vast amounts of
information including data, audio and video
across continents. The high capacity of the cable
television network can also be a new resource
for faster data traffic. We are convinced that
effective highways must start within your own
four walls, with high performance local data
communication. Based on this essential infra-
structure, you can then build access routes to national and global networks.
Leased lines
A permanently connected telecommunication circuit provided by a telecom company,
which provides point to point or multidrop (V.23) communication over long distances.
Unlike a dial-up connection you have a permanently connected circuit between two
points. This connection can be routed through exchanges or just be a direct cable con-
nection. Naturally, telecom modems with a leased line function can also utilise standard
data cabling. Full duplex communication can be achieved on both 2 and 4-wire cable.
Modems from Westermo follow several standards up to V.90, which supports transfer
rates up to 56.0 kbit/s. One modem is configured as the dialling modem and the other
the answering modem and data can be transferred continuously once a connection
has been established.
MNP Level 4:
data in blocks, block size
according to line quality.
Smaller blocks than Level 3
which results in a 20% faster
transmission rate, when free
from interference.
MNP Level 5:
as in Level 4, but with data
compression which results in
up to double the speed.
MNP Level 10:
a further development of
MNP 5 which monitors the
line dynamically and guaran-
tees error-free transmission.
Comp
ERROR
CORR
BUFFER DSP
Comp
ERROR
CORR
BUFFER DSP
The fastest communications
route is always in what is
known as direct mode.
Every stage of compression,
error correction and buffering
causes a time delay.
B A C K