Before connecting the DC supply wires, ensure that power is removed from the DC
circuit. Locate the circuit breaker of the panel board that services the equipment and
switch it to the OFF position. When connecting the DC supply wires, first connect the
ground wire to the corresponding terminal, then the positive pole and last the negative
pole. Switch the circuit breaker back to the ON position.
A readily accessible disconnect device that is suitably rated and approved should be
incorporated in the building installation.
If the DC mains are floating, the switch must disconnect both poles simultaneously.
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.
Always connect a given port to a port of the same safety status. If in doubt,
seek the assistance of a qualified safety engineer.
Always make sure that the equipment is grounded before connecting
telecommunication cables. Do not disconnect the ground connection before
disconnecting all telecommunications cables.
Some SELV and non-SELV circuits use the same connectors. Use caution when
connecting cables. Extra caution should be exercised during thunderstorms.
