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Chapter 2 - Description and Installation
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.
Battery Backup - System
External batteries may be connected to the KSU via screw terminals on the lower left area
of the KSU cabinet. In the event of a commercial power outage, the backup battery will
provide the necessary system voltage (24V +/-10%, 10A per hour) 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. It is
recommended that the battery pack be connected to the power screw terminals with
wire gauged at no less than 14 AWG. The pack must be located within 20 ft. of the KSU.
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 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.
DH S-L Instal lation
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