Westermo DDW-120 - Manual (Page 11)

11 6621-2214
Description
Functional description
The DDW-120 Ethernet Extender is the ideal solution for extending your Ethernet
network over copper cables where in the past the only option would have been fibre.
At shorter range the transfer rate will be as fast as 15.3 Mbit/s in both directions.
Depending on the quality of the cables distances up to 15 km are possible.
DDW-120 is transparent for multicast addressing, VLAN packets, VPN pass-through for
IPSec and for protocols like MODBUS/tcp and Profinet. The Link Fault Forward (LFF)
functionality in DDW-120 forwards information about the Ethernet link status, this is
sent over the SHDSL link between two DDW-120 units. In many applications it is a
requirement to disconnect the link on the other side of the SHDSL link if the primary
Ethernet link goes down.
The units will auto negotiate the transmission speed but can also be forced to choose a
slower (more reliable) or faster (less reliable) data rate.
Communication speed and distance depends on the cable characteristics, communication
reach with different cables can be calculated with DDW-tool
DDW-120 can be used in point-to-point applications or as start and termination unit
together with DDW-22x in a daisy-chain application.
Description of used nomenclature:
Noise margin:
The margin between signal and noise (dB)
CO/CPE:
CO (Central Office) answering central unit, the CO configures the CPE when establish-
ing a connection. CPE (Customer Premises Equipment) is the unit that initiates the con-
nection.