External Connections
5-9
Pr
otection Devices
5
5.3
Protection Devices
0
.
Lightning and over-voltage arrestors are used to protect the user and the system from
lightning and other electrical hazards that may occur on external circuits connected to
the system.
Any cable that passes through open air, under open ground (i.e. across parking lots,
fields, road beds, etc.), across a bridge, or along the exterior or under the non-metallic
roof of a building, is exposed to lightning and electrical hazards.
Telephone circuit protection devices fall into two distinct design categories:
Primary (lightning) protection devices that limit voltages on a telephone circuit
below levels which do not present a hazard to the user. (
Table 5-3
lists minimum
specifications).
Secondary (surge and impulse) protectors that further limit voltages on a
telephone circuit to prevent damage to electronic equipment.
Table 5-4
lists the
specifications.
Primary protection absorbs the major impact of infrequent, but dangerous, catastrophic
surges, while secondary protection suppresses constantly occurring impulses. These
impulses, while not dangerous, can cripple valuable, and in many cases, essential,
communication facilities.
1
Introduction to Primary and Secondary Protection Devices
Any circuit connected to the Coral system that is exposed to lightning or electrical
hazards must be protected with approved lightning and surge protection devices to
avoid potentially lethal hazards to all users.
Secondary protection devices should be installed on any circuit requiring primary
lightning protection, which connects electrically to an interface of the Coral system.
Summary of Contents for Coral IPx 500
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Page 58: ...2 16 Coral IPx 500 Installation Manual Site Inspection 2 NOTES...
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Page 126: ...3 6 Coral IPx 500 Installation Manual Power Supply Test 3 NOTES...
Page 152: ...3 32 Coral IPx 500 Installation Manual Installation Wrap up 3 NOTES...
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Page 184: ...5 14 Coral IPx 500 Installation Manual Protection Devices 5 NOTES...
Page 188: ...5 18 Coral IPx 500 Installation Manual Power Fail PF Transfer Circuits 5 NOTES...
Page 204: ...5 34 Coral IPx 500 Installation Manual MDFipx Units Supplied by the Manufacturer 5 NOTES...
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Page 288: ...6 32 Coral IPx 500 Installation Manual Coral IPx 500M Main Cage Description 6 NOTES...
Page 296: ...6 40 Coral IPx 500 Installation Manual Coral IPx 500X Expansion Cage Description 6 NOTES...
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Page 332: ...7 16 Coral IPx 500 Installation Manual PS500 DC Power Supply Unit 7 NOTES...
Page 350: ...7 34 Coral IPx 500 Installation Manual PS500 AC Power Supply Unit 7 NOTES...
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Page 380: ...8 4 Coral IPx 500 Installation Manual Control Cards 8 NOTES...
Page 404: ...8 28 Coral IPx 500 Installation Manual IMC8 Card Flash Erasable Software Memory Unit 8 NOTES...
Page 412: ...8 36 Coral IPx 500 Installation Manual DBX Card Database Expansion Memory Unit 8 NOTES...
Page 426: ...8 50 Coral IPx 500 Installation Manual CLA Card CoraLINK Adapter 8 NOTES...
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Page 432: ...9 4 Coral IPx 500 Installation Manual Shared Service Circuitry Installation 9 NOTES...
Page 460: ...9 32 Coral IPx 500 Installation Manual Three Way Conference Conference Circuitry 9 NOTES...
Page 490: ...9 62 Coral IPx 500 Installation Manual KB1 KB2 KB3 RS 232E Data Serial Port 9 NOTES...
Page 498: ...9 70 Coral IPx 500 Installation Manual Music Background and Music On Hold M1 M2 9 NOTES...
Page 518: ...9 90 Coral IPx 500 Installation Manual Relay Contacts RLY1 RLY2 RLY3 9 NOTES...
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Page 526: ...10 6 Coral IPx 500 Installation Manual Peripheral Card Installation 10 NOTES...
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