3Com 3C905CX User Manual

Also see for EtherLink 3C900B: Installation and operating instructions User guide

Contents

3Com 3C905CX User Manual Manual pdf 60 page image

A Specifications and Cabling Requirements54Cabling RequirementsThe cable, quality, distance, and connectors must comply with the Electronic IndustriesAssociation/Telecommunications Industries Association (EIA/TIA) 568 Commercial BuildingWiring Standard and the Technical Services Bulletin TSB38 standards.Twisted-Pair CableTwisted-pair cable consists of copper wires surrounded by an insulator. Two wires aretwisted together (the twisting prevents interference problems) to form a pair, and the pairforms a circuit that can transmit data. A cable is a bundle of one or more twisted pairssurrounded by an insulator.Unshielded twisted pair (UTP) is the most commonly used type of twisted-pair cable.Shielded twisted pair (STP) provides protection against crosstalk. Twisted-pair cable is nowcommonly used in Ethernet, Fast Ethernet, and other network topologies.The EIA/TIA defines five categories of unshielded twisted-pair cable.EnvironmentOperating temperature 32˚ to 158˚ F (0˚ to 70˚ C)Storage temperature –22˚ to 194˚ F (–30˚ to 90˚ C)Operating humidity 10 to 90% noncondensingStorage humidity 10 to 90% noncondensingAltitude –984 ft to 9,840 ft (–300 to 3,000 m)Standards Conformance IEEE 803.3x flow control Microsoft PC98 PCI 2.1 DMI 2.0 sCategory Use1 Traditional telephone cable.2 Data transmission up to 4 MHz.3 Voice and data transmission up to 25 MHz. The cable typically has four pairs of wires.Category 3 is the most common type of installed cable found in older corporatewiring schemes.4 Voice and data transmission up to 33 MHz. The cable normally has four pairs of wire.This grade of UTP is not common.5 Voice and data transmission up to 125 MHz. The cable normally has four pairs ofcopper wire and three twists per foot. Category 5 UTP is the most popular cable usedin new installations today.