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ST300 SPIDER
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6. REFERENCE INFORMATION
6.1. TWISTED PAIR CABLING
Twisted pair cabling is a type of cabling that consists of one or several twisted pairs, i.e., insulated
conductor strands twisted together with relatively few windings per length unit, enclosed in an outer
plastic casing.
The idea is to increase consistency between two cores of a pair, as electromagnetic interference from
external sources will affect them equally, and to reduce such interference.
In order to reduce interaction of different pairs in a bundled twisted pair cable (due to periodic mutual
proximity of conductor cores from different twisted pairs), cables of the 5th or higher category utilise
twisted pairs with different numbers of windings per unit of length.
Twisted pair cables are used in modern structured cabling systems, for telecommunications and
computer networking, in various transmission technologies, including Ethernet, Arcnet, and Token Ring.
Owing to their inexpensiveness and ease of mounting, these cables are at present the most common
choice for wired LANs.
The most typical are twisted pair cables consisting of one, two, and four twisted pairs.
6.2. RJ STANDARDS
RJ (Registered Jack) is a standardized physical network interface
comprising both connectors (“plug” and “socket”) and their connection
scheme. It is widely used in telecommunications. The best known standards
of this kind are RJ11, RJ14, RJ25, and RJ45.
connector standard
name
type no. of
cores
purpose
RJ9 4P4C 4 connecting telephone handsets to their bases
RJ11 6P2C 2 connecting two-wire telephone sets to the
network
RJ12 6P6C 6 connecting 6-wire telephone sets
RJ14 6P4C 4 connecting 4-wire telephone sets
RJ21 50-contact connecting PBX’s or other telecom equipment
(sometimes also called “Telco”, or “Amphenol”)
RJ25 6P6C 6 connecting 6-wire telephone sets
RJ45S 8P4C,
keyed
4 connecting modems
RJ45 8P8C 8 creating local area networks
RJ50 10P10C 10 used by UPS units made by American Power
Conversion and Eaton Corporation
In the notation “хPyC”, the letter “P” stands for “Positions” in a plug, and “C”, for “Contacts” in a
socket.
6.3. WIRING SCHEME OF A 4 TWISTED-PAIR CABLE
For 10Base-T and 100Base-T Ethernet standards, four cores (orange and green pairs) are used, while
the remaining four are reserved for the Gigabit Ethernet (1000Base-T) standard. There are two wiring
schemes, 568A and 568B. The latter is more frequent.