User Manual

Connection of Data and Telecommunications Cables
Data and telecommunication interfaces are classified according to their safety status.
The following table lists the status of several standard interfaces. If the status of a given
port differs from the standard one, a notice will be given in the manual.
Ports Safety Status
V.11, V.28, V.35, V.36, RS-530,
X.21, 10 BaseT, 100 BaseT,
Unbalanced E1, E2, E3, STM, DS-
2, DS-3, S-Interface ISDN,
Analog voice E&M
SELV Safety Extra Low Voltage:
Ports which do not present a safety hazard.
Usually up to 30 VAC or 60 VDC.
xDSL (without feeding voltage),
Balanced E1, T1, Sub E1/T1
TNV-1 Telecommunication Network Voltage-1:
Ports whose normal operating voltage is
within the limits of SELV, on which overvoltages
from telecommunications networks are possible.
FXS (Foreign Exchange
Subscriber)
TNV-2 Telecommunication Network Voltage-2:
Ports whose normal operating voltage
exceeds the limits of SELV (usually up to 120 VDC
or telephone ringing voltages), on which
overvoltages from telecommunication networks
are not possible. These ports are not permitted
to be directly connected to external telephone and
data lines.
FXO (Foreign Exchange Office),
xDSL (with feeding voltage),
U-Interface ISDN
TNV-3 Telecommunication Network Voltage-3:
Ports whose normal operating voltage
exceeds the limits of SELV (usually up to 120 VDC
or telephone ringing voltages), on which
overvoltages from telecommunication networks
are possible.
The signals between the IDU and ODU are TNV-1.
Always connect a given port to a port of the same safety status. If in doubt, seek the
assistance of a qualified safety engineer.
Note