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2-26
2. KSU Grounding
To ensure that the system will operate properly, a good earth ground is recommended.
The Telco protector ground terminal or a metallic COLD water pipe will usually provide a
reliable ground path. If cold water pipe is used, carefully check that the pipe does not
contain insulated joints that could isolate the ground. In the absence of the cold water
pipe, a ground rod or other source may be used. A No. 8 AWG copper wire should be used
between the ground source and the KSU.
Voltage Surge/Spike Protection
To reduce the effects of AC voltage surges and spikes that may cause system
malfunctions, false logic, and/or damage to the electronic components, it is
recommended that a separately sourced surge/spike protector be installed. Check the
manufacturer's specifications to ensure that the device meets the following
requirements:
The power cord should not be used with a 3-wire to 2-wire plug adapter.
A power line surge protector should be used to protect the power supply from
electrical surges. The surge protector should be installed in accordance with the
manufacturer's instructions and applicable local electrical codes.
Clamp voltage transients at 300V within 5 nsec. when exposed to wave-forms as
described in the ANSI/IEEE Standard C62.41-1980 (IEEE 587).
Reduce RFI/EMI noise by at least 20 dB at frequencies between 5 kHz and 30 MHz.
3. Battery Backup - System
External batteries may be connected to the KSU via the optional Starplus VC61101
Battery Charging Unit (BCU). This unit may be equipped with batteries sized to meet the
particular customer requirements. The approximate time, in back-up hours, is located in
Table 2-11. In the event of a commercial power outage, the BCU will provide the
necessary system voltage (24V) to allow full feature key telephone operation until AC
power is restored or the battery voltage reaches minimum voltage thresholds and is
automatically disconnected to avoid battery damage. This threshold is approximately 21
to 21.5V. The amount of system battery operation time is dependent on several factors:
Number and type of key telephones installed
System traffic load
Age of external batteries
Equipment Room Temperature
Amp/Hour rating of external batteries
Recovery time since last AC power interruption
The Starplus VC61106 BCU is designed for use with the DHS system. Follow the
instructions supplied with the BCU to install batteries in that unit. Consult Table 2-11 for
system operating current draw to select the right battery size for the desired back up
duration.
The ground wire should be kept as short as possible and can be connected
to the ground lug located on the bottom of the KSU. Check your local
grounding regulations before installing the ground wire.
DHS Installation
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