RS900 Family Installation Guide
3 Ethernet Ports
3.1 Ethernet over VDSL Port
3.1.1 Overview
The Ethernet over VDSL (EoVDSL) port operates in pairs with one unit configured as the
Master and the other as the Slave. In VDSL literature the terms Central Office (CO) or
Line Termination (LT) are used interchangeably for the Master and the terms Customer
Premise Equipment (CPE) or Network Termination (NT) are used interchangeably for
the Slave. The Master unit dictates the line configuration settings to the Slave so all
EoVDSL configuration is done on the Master. Data flowing from the Master to the Slave
is designated “downstream” while data flowing from the Slave to the Master is
designated “upstream”.
RuggedCom offers two flavours of VDSL: Universal EoVDSL and Long-Reach EoVDSL.
Universal EoVDSL ports are Master/Slave selectable and offer symmetric data rates up
to 35 Mbps with distances up to 2.5 km. Long-Reach EoVDSL ports are fixed as either
Master or Slave but offer asymmetric data rates up to 40 Mbps with distances up to 5
km. The Universal and Long-Reach EoVDSL ports are physically indistinguishable from
each other; however, you can determine which port you have either from the order code
or through the software.
3.1.2 Wiring
VDSL operates over 2-wire Category 3 (CAT-3) or higher twisted-pair wiring. Other
twisted-pair wiring with similar characteristics may work although the performance will
vary depending on the cable characteristics and distance.
Wiring Tips:
Twisted-pairs are effective way of reducing both magnetic and capacitive
interference because it reduces the magnetic loop area to nearly zero and ensures a
consistent distribution of capacitances to both ground and other sources. Therefore,
ensure twisting is consistent throughout cable length.
Open leads (also known as bridged taps or drop-lines) along the length of the cable
will cause an impedance mismatch and result in VDSL signal degradation.
Ensure the cable impedance is consistent throughout the run; Avoid mixing different
wiring (for example, wiring with different gauges) in cable runs because this will
cause an impedance mismatch and result in VDSL signal degradation.
Ensure wiring is adequately separated power and control circuits. Switching spikes
and surges in power and control circuits can couple noise onto the VDSL line
causing interruptions in communications.
Lower speeds are less susceptible to interference and will transmit greater distances
over the same wiring than higher speeds. Use the minimum speed that will provide
adequate data transfer speed.
2010 RuggedCom Inc.
22
Rev107
