Cisco question

Discussion in 'Cisco' started by, Feb 24, 2005.

  1. Guest

    I guess the answer is
    1.the lowest frequencies that the cable is rated to support
    2.that the white-orange/orange pair is attached first

    what do you guy think?

    1. Which frequencies are used by a cable tester to measure attenuation?

    the lowest frequencies that the cable is rated to support
    the highest frequencies that the cable is rated to support
    frequencies from 20 Hz to 20 kHz in 20 Hz increments
    10 kHz and 100 GHz

    2. To ensure reliable LAN communications, what should a technician be
    looking for when attaching connectors to the ends of UTP cable?

    that the white-orange/orange pair is attached first
    that the wire pairs remain twisted as much as possible
    that one end of the shield is properly ground but not the other
    that 50 ohm termination resistors are on both ends
    , Feb 24, 2005
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  2. BradReeseCom Guest

    Archive-name: LANs/cabling-faq
    Posting-Frequency: monthly
    Last-modified: 1995/03/05

    C A B L I N G F A Q

    Version 950305

    This is a Frequently Asked Questions (FAQ) document for the
    comp.dcom.cabling newsgroup. Topics covered include the
    types of cables (fiber, coax, copper, unshielded twisted
    pair-UTP, shielded twisted pair), installation techniques,
    standards as well as fire and building safety codes.

    Prepared and maintained by Peter Macaulay ()
    Constructive comments/updates are welcomed.

    0.1 Recent Updates

    The most recent changes are on the top of this list for easier
    identification of the new stuff (push down stack). Format of
    the version is year, month, day.

    950305 - added approval, cable testing
    950124 - added bending radius specs, ISDN cabling
    950110 - added headers required for posting
    - expanded references with much help from Evan Gamblin

    0.2 Copyright

    Copyright (c) 1995 by Peter Macaulay, all rights reserved.

    This FAQ may be posted to any USENET newsgroup, on-line service,
    or BBS as long as it is posted in its entirety and includes this
    copyright statement.

    0.3 Disclaimer

    This article is provided as is without any express or implied
    warranties. While every effort has been taken to ensure the
    accuracy of the information contained in this article, the
    author and contributors assume no responsibility for errors
    or omissions, or for damages resulting from the use of the
    information contained herein.


    0.4 Acknowledgments

    (Bill Hughes)
    (Evan Gamblin)
    (John Lundgren)
    (Mike Barker)
    (Henriecus Koeman)

    0.1 Recent Updates
    0.2 Copyright
    0.3 Disclaimer
    0.4 Acknowledgments
    1.0 Cable Types
    2.0 Cable Ratings
    3.0 National Electrical Code (NEC)
    4.0 Not Used (Blank)
    5.0 Specific Cable Classifications
    6.0 Cable Conductors
    7.0 Vendor Specific Suggestions
    8.0 Cabling Standards
    9.0 Standard EIA/TIA 568
    10.0 Birds and Bees (Plugs vs. Jacks)
    11.0 Standard Networking Configurations
    12.0 Ethernet 10Base-T Cabling
    13.0 Category Specifications
    14.0 Sources for the EIA/TIA 568 Standards Documents
    15.0 Cable Test Equipment
    16.0 Cable Testers for Category 5
    17.0 Typical Wiring Layout
    18.0 How Far Away Should Cable be Installed from an EMI Source
    19.0 What is the Minimum Bending Radius for a Cable?
    20.0 Fiber Optic Cable
    21.0 ISDN Cabling
    22.0 Testing Unshielded Twisted Pair Cables
    23.0 - 29.0 Not Used (Blank)
    30.0 Sources of Additional Information


    Subject: 1.0 Cable Types

    Communications Cable: primarily for telephone cable
    Class 2 Cable: signaling cable primarily for data communications
    Riser: vertical shaft used to route cable between floors
    Plenum: Heating, Ventilation, Air Conditioning (HVAC) air return
    area -- mostly drop ceilings. Also below raised floors
    (where the underfloor area is used for ventilation).


    Subject: 2.0 Cable Ratings

    (Or What Are Those Codes Printed On My Cables?)
    In the Hollywood movie _Towering Infernio_ (starring O.J.Simpson)
    a fire spread from floor to floor using the building cables. This

    will not happen again (we hope) since everyone is using fire rated

    cables! These are important specifications if you are responsible

    for defining a cable installation.

    If interfloor penetrations are properly _firestopped_, the
    cables can burn, but the fire will not pass the firestopping.

    UL-910, FT-4 and FT-6 say nothing about the type or volume of
    combustion products produced. All they cover is performance on a
    flamespread test.


    The US National Fire Protection Association (NFPA) revises the
    National Electrical Code (NEC) every 3 years. The NEC defines
    classifications of cable as per UL tests.

    The Canadian Standards Association (CSA) defines Premise
    Cord (PCC) standards for physical wire tests. These are printed
    on the cable as CSA-PCC-FT6.

    FT4 = Flame Test 4 is described in CSA C22.2 0.3-1992
    FT6 = Flame Test 6 is described in NFPA 262-1985 and ULC S102.4
    Physical Wire Tests C22.2 214-M-1990. These CSA documents can
    be ordered from the CSA. See sources below.

    <<<Any comments on standards from other parts of the world?>>>


    Subject: 3.0 National Electrical Code (NEC)

    1993 National Electrical Code

    Article 725, Class 2
    725-38(b)1 CL2X Class 2 cable, limited use
    725-38(b)1 CL2 Class 2 cable
    725-38(b)2 CL2R Class 2 riser cable
    725-38(b)3 CL2P Class 2 plenum cable

    Article 800
    800-3(b)1 CMX Communications cable limited use
    800-3(b)1 CM Communications cable
    800-3(b)2 CMR Communications riser cable
    800-3(b)3 CMP Communications plenum cable

    OFNP (Optical Fiber Nonconductive Plenum)
    OFNR (Optical Fiber Nonconductive Riser)


    Subject: 4.0 Not Used (Blank)


    Subject: 5.0 Specific Cable Classifications

    CMS, CL2X (Restricted Cable) must be enclosed in conduit,
    up to 10 feet exposed; must pass UL 1581 VW-1 test

    CM, CL2 (General Purpose Cable) for use in areas other
    than risers or plenums; must pass UL 1581 vertical tray test

    CMR, CL2R (Riser Cable) for cable in vertical shafts;
    must pass UL test method 1666

    CMP, CL2P (Plenum Cable) for use in plenum areas (air ducts);
    must pass UL 910 test for smoke and flame spread


    Subject: 6.0 Cable Conductors

    Cable conductor gauge is specified as AWG (American Wire Gauge).
    A higher number is a smaller diameter. Telephone cable used
    is typically 24 or 26 AWG, whereas household electrical wiring is
    typically 12 or 14 AWG.


    Subject: 7.0 Vendor Specific Suggestions

    AMP NETCONNECT Open Cabling System
    HP SiteWire
    AT&T PDS
    IBM STP (Type 1, Type 2, etc)
    Northern Telcom IBDN


    Subject: 8.0 Cabling Standards

    American National Standards Institute (ANSI)
    Electronic Industry Association (EIA)
    Telecommunications Industry Association (TIA)

    Current specification is the ANSI/EIA/TIA-568-1991 Standard
    _Commercial Building Telecommunications Wiring Standard_ and
    two Tech Sys Bulletins:

    _Additional Cable Specifications for Unshielded Twisted-Pair
    EIA/TIA Tech Sys Bulletin TSB-36, Nov 1991
    [Transmission Characteristics of Category 3-5 UTP cables]

    _Additional Transmission Specifications for UTP Connecting
    EIA/TIA Tech Sys Bulletin TSB-40A, Dec 1993
    (Performance of Connectors and Patch Panels Above 20 MHz)

    Extended Specifications for 150-ohm STP Cables and Data
    Connectors - EIA/TIA Tech Sys Bulletin TSB-53, 1992 [Type 1A

    EIA-570: Residential and Light Commercial Telecommunications
    Wiring Standard - EIA/TIA, 1991

    EIA-606: Telecommunications Administration Standard for Commercial

    Buildings - EIA/TIA (was PN-2290)

    EIA-607: - Commercial Building Grounding and Bonding Requirements
    for Telecommunications - EIA/TIA

    EIA/TIA PN-2840 - [draft for the EIA-568-A standard, incorporating

    TSB-36 and -40A, expected in early 1995]

    EIA/TIA PN-2840A - [draft for next version of the EIA-568-A

    American National Standards Institute (ANSI)/
    National Fire Protection Assoc. (NFPA):
    70 National Electrical Code (1993)
    78 Lightning Protection Code

    Canadian Standards Association (CSA):
    C22.1-1994 Canadian Electrical Code, Part 1

    CAN/CSA-T527: Bonding and Grounding for Telecommunications
    in Commercial Buildings - Canadian Standards Assoc.
    [harmonized with EIA-607]

    CAN/CSA-T528: Telecommunications Administration Standards for
    Commercial Buildings - CSA, Jan 1993 [harmonized with EIA-606]

    CAN/CSA-T529-M91: Design Guidelines for Telecommunications Wiring
    System in Commercial Buildings, - CSA [harmonized with EIA-568]

    CAN/CSA-T530-M90: Building Facilities, Design Guidelines for
    Telecommunications - CSA, 1990 [harmonized with EIA-569]

    ISO/IEC 11801: [international equivalent of EIA-568 and CSA T-529,

    includes 120 ohm Screened Twisted Pair cable]

    IEC 603-7, Part 7 - [Modular connector physical dimensions,
    and electrical characteristics. Level A: 750 mating cycles min;
    B: 2,500 min; C: 10,000 min.]

    ISO 8877: Information Processing Systems - Interface Connector and

    Contact Assignment for ISDN Basic access interface located at
    reference points S and T - International Organization for
    Standardization [same pin/pair assignments for 8-line modular
    connector as EIA T-568A]

    National Electrical Safety Code Handbook (NESC):
    Institute of Electrical and Electronic Engineers (IEEE)/
    American National Standards Institute (ANSI):
    C2-1993 National Electrical Safety Code
    ISBN 1-55937-210-9 (order # SH15172)
    [In USA, governs the area between the property line and the
    building entrance]

    National Research Council of Canada, Institute for Research in
    Construction (NRC-IRC):
    National Building Code of Canada (1990) - order NRCC 30619
    Supplement to the National Building Code of Canada (1990)
    - order NRCC 30629
    National Fire Code of Canada (1990) - order NRCC 30621

    A Guide to Premises Distribution
    - NCR/AT&T order #555-400-021, Apr 1988

    Building Network Design - Bell Canada, 1992

    The Corporate Cabling Guide - M. McElroy,
    Artech House, ISBN 0-89006-663-9, Dec 1992

    Telecommunications Distribution Methods Manual (1050 pages)
    - Building Industries Consulting Service International (BICSI),

    Universal Transport System Design Guide, Release II
    - Siecor Corp, 1991 [fiber-optic cable plant]

    Requirements Beyond Jacks and Cable: an Installation Guide
    - Leviton Telecom, Second edition, T15-00004-003, Jan 1994

    SiteWire Twisted-pair Installation Guide
    - Hewlett-Packard, p/n 5959-2208, Jan 1988

    SiteWire Planning Guide - Hewlett-Packard, p/n 5959-2201,
    Sept 1989

    Tech Ref Guide for Workgroup LANs
    - Hewlett-Packard, p/n 5091-0663E, Apr 1991

    Tech Ref Guide for Site LANs and MultiSite LANs
    - Hewlett-Packard, p/n 5091-0666E, Apr 1991

    Understanding Fiber Optics - J. Hecht
    Howard Sams & Co., ISBN 0-672-27066-8, 1988

    Optical Fiber Communications, I & II - S. Miller
    Academic Press, ISBN 0-12-497350-7 & -5

    Optical Fiber Splices and Connectors: Theory & Methods -
    C. M. Miller, Marcel Dekker, 1986

    Principles of Optical Fiber Measurements - D. Marcuse
    Academic Press, ISBN 0-12-470-980-X, 1981

    Single-Mode Fibers: Fundamentals - E. G. Neumann
    Springer-Verlag, ISBN 0-387-18745-6, 1988

    CATV Cable Construction Manual, 3rd edition - Comm/Scope Inc.,
    [Outside Plant tools and procedures: trenching, boring, installing

    aerial and buried cable]

    Marking Guide: Wire and Cable - Underwriters Labs, 1993
    [How to interpret UL cable jacket markings]


    Subject: 9.0 Standard EIA/TIA 568

    The ANSI/EIA/TIA-568-1991 Standard _Commercial Building
    Telecommunications Wiring Standard_ defines pinouts;

    9.1 Standard EIA/TIA T568A
    (also called ISDN, previously called EIA)

    Pin Wire Color
    === ==========
    /--T3 1 White/Green
    Pair3 \--R3 2 Green
    /----------T2 3 White/Orange
    / /-R1 4 Blue
    pair2 \ pair1 \-T1 5 White/Blue
    \----------R2 6 Orange
    /--T4 7 White/Brown
    pair4 \--R4 8 Brown

    9.2 Standard EIA/TIA T568B
    (also called AT&T specification, previously called 258A)

    /--T2 1 White/Orange
    pair2 \--R2 2 Orange
    /----------T3 3 White/Green
    / /-R1 4 Blue
    pair3 \ pair1 \-T1 5 White/Blue
    \----------R3 6 Green
    /--T4 7 White/Brown
    pair4 \--R4 8 Brown

    9.3 USOC (Universal Service Order Code)

    8-pins 6-pins
    | |
    /-------------T4 1 White/Brown
    / /---------T3 2 1 White/Green
    / / /-----T2 3 2 White/Orange
    / / / /-R1 4 3 Blue
    pr4\ pr3\ pr2\ pr1\-T1 5 4 White/Blue
    \ \ \-----R2 6 5 Orange
    \ \---------R3 7 6 Green
    \-------------R4 8 Brown


    Subject: 10.0 Birds and Bees (Plugs vs. Jacks)

    The EIA/TIA specifies an RJ-45 (ISO 8877) connector for Unshielded

    Twisted Pair (UTP) cable. The plug is the male component crimped
    on the end of the cable while the jack is the female component in
    a wall plate or patch panel, etc. Here is the pin numbering to
    answer the question, where is pin one?

    Plug Jack
    (Looking at connector (Looking at cavity
    end with the cable in the wall)
    running away from you)

    ---------- / ----------
    | 87654321 | | 12345678 |
    |__ __|/ |/_ /_|
    |____| |/___|


    Subject: 11.0 Standard Networking Configurations

    With reference to T568B above;
    ATM 155Mbps uses pairs 2 and 4 (pins 1-2, 7-8)
    Ethernet 10Base-T uses pairs 2 and 3 (pins 1-2, 3-6)
    Ethernet 100Base-T4 uses pairs 2 and 3 (4T+) (pins 1-2, 3-6)
    Ethernet 100Base-T8 uses pairs 1,2,3 and 4 (pins 4-5, 1-2, 3-6,
    Token-Ring uses pairs 1 and 3 (pins 4-5, 3-6)
    TP-PMD uses pairs 2 and 4 (pins 1-2, 7-8)
    100VG-AnyLAN uses pairs 1,2,3 and 4 (pins 4-5, 1-2, 3-6, 7-8)


    Subject: 12.0 Ethernet 10Base-T Cabling

    12.1 Ethernet 10Base-T Straight Thru patch cord (T568B colors);

    RJ45 Plug RJ45 Plug
    ========= =========
    /--T2 1 ... White/Orange .... 1 TxData +
    pair2 \--R2 2 ... Orange .......... 2 TxData -
    /----------T3 3 ... White/Green ..... 3 RecvData +
    / R1 4 Blue 4
    \ pair3 T1 5 White/Blue 5
    \----------R3 6 ... Green ........... 6 RecvData -
    T4 7 White/Brown 7
    R4 8 Brown 8

    12.2 Ethernet 10Base-T Crossover patch cord;
    This cable can be used to cascade hubs, or for connecting
    two Ethernet stations back-to-back without a hub (ideal for
    two station Doom!) Note pin numbering in item 10.0 above.

    RJ45 Plug 1 Tx+ -------------- Rx+ 3 RJ45 Plug
    2 Tx- -------------- Rx- 6
    3 Rx+ -------------- Tx+ 1
    6 Rx- -------------- Tx- 2

    12.3 Ethernet 10Base-T to USOC Crossover patch cord;

    RJ45 8-pin Plug 1 ---White/Orange--- 2 USOC 6-pin Plug
    ^ 2 ------Orange------ 5 ^
    3 ---White/Green---- 1
    6 ------Green------- 6

    12.4 Crossover Implementation
    A simple way to make a crossover patch cable is to take a
    dual-jack surface mount box and make the crossover between
    the two jacks. This allows using standard patch cables, and
    avoids the nuisance of having a crossover cable find its way
    into use in place of a regular patch cable.

    12.5 Stranded Patch Cables
    The color code used in stranded patch cables is different from
    solid-conductor cables. For NorTel Digital Patch Cable (DPC),
    the coding is;
    Pair 1: Green & Red
    Pair 2: Yellow & Black
    Pair 3: Blue & Orange
    Pair 4: Brown & Gray


    Subject: 13.0 Category Specifications

    EIA/TIA Category Specification provide for the following cable
    transmission speeds with specifications (Note prior to Jan94
    UL and Anixter developed a LEVEL system which has been dropped
    or harmonized with the CATEGORY system);

    Category 1 = No performance criteria
    Category 2 = Rated to 1 MHz (used for telephone wiring)
    Category 3 = Rated to 16 MHz (used for Ethernet 10Base-T)
    Category 4 = Rated to 20 MHz (used for Token-Ring, 10Base-T)
    Category 5 = Rated to 100 MHz (used for 100Base-T, 10Base-T)

    UL LAN Cable Certification Program - Underwriters Laboratories
    publication 200-120 30M/3/92, 1992 [characteristics of Cat 3-5


    Subject: 14.0 Sources for the EIA/TIA 568 Standards Documents

    EIA Standards Sales Office -or-
    Global Engineering Documents (east or west coast offices)
    (See addresses in sources below)


    Subject: 15.0 Cable Test Equipment

    15.1 DVM
    DVM = Digital Volt Meter (measures volts)

    15.2 DMM
    DMM = Digital Multi Meter (measures volts, ohm, capacitance,
    and some measure frequency)

    15.3 TDR
    TDR = Time Domain Reflectometer (measures cable lengths,
    locates impedance mismatches).

    15.4 Tone Generator
    Tone Generator and Inductive Amplifier = Used to trace cable
    follow cables hidden in walls or ceiling. The tone generator will
    typically put a 2 kHz audio tone on the cable under test, the
    inductive amp detects and plays this through a built-in speaker.

    15.5 Wirmap Tester
    Wiremap tester: checks a cable for open or short circuits,
    pairs, crossed pairs and split pairs.

    A least-cost wiremap type tester that detects split pairs
    (using a NEXT test) is the Fluke 610, at $400. MOD-TAP and UNICOM

    make a similar device.

    15.6 Noise Tester
    Noise tests, 10Base-T: the standard sets limits for how often
    noise events can occur, and their size, in several frequency
    Various handheld cable testers are able to perform these tests.

    15.7 Butt-in
    Butt-in set: a telephone handset that when placed in series with a

    battery (such as the one in a tone generator), allows voice
    over a copper cable pair. Can be used for temporary phone service
    in a
    wiring closet.

    15.7 Fiber Testing
    See section 20.7 for fiber optic test equipment.


    Subject: 16.0 Cable Testers for Category 5

    _LANcat V_ by Datacom Technologies
    Everett, WA
    Tel: 800/468-5557

    _DSP100_ by Fluke Corporation
    P.O. Box 9090
    Everett, WA 98206-9090
    Tel: 206/356-5400 800/44-FLUKE

    _PentaScanner_ by Microtest, Inc
    4747 North 22nd St,
    Phoenix, AZ 85016
    Tel: 602/952-6400 800/526-9675

    _WireScope100_ by Scope Communications, Inc
    100 Otis St,
    Northboro, MA 01532
    Tel: 508/393-1236

    _LANTech PRO_ by Wavetek, Inc
    9145 Balboa Ave
    San Diego, CA 92123
    Tel: 619/279-2200 800/854-2708

    At present some vendors are calling their instruments _CAT 5
    conformance_ testing devices. Be aware that there is an on-going
    standards process to define field testing of CAT 5 cables. These
    standards or guidelines (currently called PN-3287) will not be
    complete until the June 1995 timeframe.

    The TIA TSB number will be TSB-67 when PN-3287 is approved.

    The standard is expected to define two accuracy levels of test
    equipment, and provide minimum performance standards for each.
    Current test equipment is likely to fall in the lower level. The
    higher class (_Accuracy Level II_) is intended for subsequent
    generations of test equipment capable of performing the
    increasingly numerous and stringent tests now being developed.


    Subject: 17.0 Typical Wiring Layout

    17.1 Wiring Layout

    ......Wiring Closet.............. ....User Work


    Where ...
    HUB = concentrator
    PANEL = RJ-45 Modular Patch Panel

    BLOCK = Telco Splice Block (Typically 25-pair)

    Crossconnect: NorTel BIX1A, AT&T 110 and similar crossconnect
    blocks accommodate 4-pair, 25-pair or larger cables on the
    same mount. The same type of mount can be used for the voice
    field as well as data.

    Telephone-only (66) blocks are seldom used except for
    low-speed data circuits such as are used for IBM 3270 terminals.
    The newer types of crossconnect mentioned above cost about the
    same and accommodates growth much better. (The standard AT&T 110
    and its BIX equivalent are rated at Cat 5).

    LOBE CABLE = Cable run from user wall plate to wiring closet
    WALL = User area wall face plate
    STATION = User workstation network adapter
    =====> = RJ-45 connector
    =====+ = Punch down termination (also called an insulation-
    displacement/displacing connector, or IDC).

    17.2 Crossconnect Field Colors
    The color of label used on a crossconnect field identifies the
    field's function. The cabling administration standard (CSA T-528
    & EIA-606) lists the colors and functions as:

    Blue Horizontal voice cables
    Brown Interbuilding backbone
    Gray Second-level backbone
    Green Network connections & auxiliary circuits
    Orange Demarcation point, telephone cable from Central Office
    Purple First-level backbone
    Red Key-type telephone systems
    Silver or
    White Horizontal data cables, computer & PBX equipment
    Yellow Auxiliary, maintenance & security alarms


    Subject: 18.0 How Far Away Should Cable be Installed from an EMI Source

    Northern Telecom IBDN User Manual contains an Appendix D titled
    _UTP Separation Guidelines From EMI Sources_. The values are the
    same as the cabling pathways standard, EIA-569, table 4.8-5.

    Minimum Separation Distance
    from Power Source at 480V or less
    CONDITION <2kVA 2-5kVA >5kVA
    Unshielded power lines or
    electrical equipment in proximity
    to open or non-metal pathways 5 in. 12 in. 24 in.
    (12.7 cm) (30.5 cm) (61 cm)
    Unshielded power lines or
    electrical equipment in proximity
    to grounded metal conduit pathway 2.5 in. 6 in. 12 in.
    (6.4 cm) (15.2 cm) (30.5 cm)
    Power lines enclosed in a grounded
    metal conduit (or equivalent
    shielding) in proximity
    to grounded metal conduit pathway - 6 in. 12 in.
    - (15.2 cm) (30.5 cm)

    Transformers & electric motors <------- 40-in (1.02 m)

    Fluorescent lighting <------- 12-in (30.5 cm)

    Source: Integrated Building Distribution Network (IBDN) User
    - Northern Telecom, doc # IBDN-UM-9105, 1991.

    The EIA/TIA working group revising the EIA-569 standard is using
    results of field and lab tests to update the recommendations. The
    target date for completion is Dec 1995.


    Subject: 19.0 What is the Minimum Bending Radius for a Cable?

    According to EIA SP-2840A (a draft version of EIA-568-x) the
    bend radius for UTP is 4 x cable outside diameter, about one inch.

    For multipair cables the minimum bending radius is 10 x outside

    SP-2840A gives minimum bend radii for Type 1A Shielded Twisted
    (100 Mb/s STP) of 7.5 cm (3-in) for non-plenum cable, 15 cm (6-in)

    for the stiffer plenum-rated kind.

    For fiber optic cables not in tension, the minimum bend radius is
    10 x
    diameter; cables loaded in tension may not be bent at less than 20
    diameter. SP-2840A states that no f/o cable will be bent on a
    less than 3.0 cm (1.18-in).

    The ISO DIS 11801 standard, Section 7.1 General specs for 100 ohm
    and 120 ohm balanced cable lists three different minimum bend
    Minimum for pulling during installation is 8x cable diameter, min
    installed radius is 6x for riser cable, 4x for horizontal.

    For fiber optic cables not in tension, the minimum bend radius is
    10 x diameter; cables loaded in tension may not be bent at less
    than 20 x diameter. SP-2840A states that no f/o cable will be
    bent on a radius less than 3.0 cm (1.18-in).

    Some manufacturers recommendations differ from the above, so it is

    worth checking the spec sheet for the cable you plan to use.


    Subject: 20.0 Fiber Optic Cable

    20.1 Multimode (MM) Fiber
    Step index or graded index fiber. In North America the most common

    size is 62.5/125; in Europe, 50/125 is often used. These numbers
    represent the diameter of the core (62.5) and diameter of the
    cladding (125) in microns. Multimode fiber is typically used in
    applications such as local area networks, at distances less than 2

    20.2 Single Mode (SM) Fiber
    Single mode fiber has a very small core. Typical values are
    5-10 microns. Single mode fiber has a much higher capacity and
    allows longer distances than multimode fiber. Typically used
    for wide area networks such as telephone company switch to switch
    connections and cable TV (CATV).

    20.3 Loose Buffer
    The fiber is contained in a plastic tube for protection.
    To give better waterproofing protection to the fiber, the space
    between the tubes is sometimes gel-filled. Typical applications
    are outside installations. One drawback of loose buffer
    is a larger bending radius. Gel-filled cable requires the
    to spend time cleaning and drying the individual cables, and
    cleaning up the site afterwards.

    20.4 Tight Buffer
    Buffer layers of plastic and yarn material are applied over the
    Results in a smaller cable diameter with a smaller bending radius.

    Typical applications are patch cords and local area network
    At least one mfr. produces this type of cable for inside/outside

    20.5 Ribbon Cable
    Typically 12 coated fibers are bonded together to form a
    ribbon. There are higher density ribbons (x100) which have
    the advantage of being mass-terminated into array connectors.
    A disadvantage is that they are often harder, and require special
    tools to terminate and splice.

    20.6 Fiber Connectors
    There are a lot of different types of connectors, but the ones
    commonly found in LAN/MAN/WAN installations are:

    FSD - Fixed Shroud Device, such as the FDDI MIC dual-fiber
    SC - A push-pull connector. The international standard.
    The SC connectors are recommended in SP-2840A. The SC
    connector has the advantage (over ST) of being duplexed
    into a single connector clip with both transmit/receive fibers.
    SMA - Threaded connector, not much used anymore because of losses
    that change with each disconnection and reconnection.
    ST - Keyed, bayonet-style connector, very commonly used.

    20.7 Fiber Optic Test Equipment
    Continuity tester: used to identify a fiber, and detect a break.
    One type resembles a f/o connector attached to a flashlight.

    Fault locator: used to determine exact location of a break.
    Works by shining a very bright visible light into the strand.
    At the break, this light is visible through the cable jacket.

    Tone Generator and Tracer: used to identify a cable midspan or
    to locate a strand at its far end. Similar in purpose to the
    tone testers used on copper cable. The tone generator imposes
    a steady or warbling audio tone on light passing down the cable.
    The tracer detects and recovers the tone from light lost through
    the cable jacket as a result of bending the cable slightly.

    Optical Source and Power Meter: used to measure the end-to-end
    loss through a f/o strand, or system of cable, connectors and
    patch cables. Measurements are more accurate than an OTDR.

    Optical Time Domain Reflectometer (OTDR): used to measure the
    of a cable, and detect any flaws in it. Can also be used to
    end-to-end loss, although less accurately than a power meter.

    Fiber Talk set: allows using a pair of f/o strands as a telephone

    Fiber Optic Testing, standards: see EIA-455-171 (FOTP-171), EIA


    Subject: 21.0 ISDN Cabling

    21.1 ISDN U-loop
    ISDN Basic Rate Interface (BRI) is provided by a carrier from
    a central office (CO) switch to the customer premise with a
    two wire U-loop RJ-45 connector on the center pins 4-5.

    RJ45 Plug
    1 N/C
    2 N/C
    3 N/C
    4 U-loop network connection
    5 U-loop network connection
    6 N/C
    7 N/C
    8 N/C

    21.2 ISDN Network Termination (NT)
    The Network Termination is a Power Supply and NT1. In North
    America this functionality can be provided in the terminal
    equipment (i.e. ISDN digital modem) or separate as follows;
    ________ ________
    | Power | | |========== TE
    =========| Supply |============| NT1 |
    U-loop |________| U+PS2 |________|======== S/T bus
    2-wire 4-wire 4-wire

    RJ45 Plug for U+PS2
    1 N/C
    2 N/C
    3 N/C
    4 U-loop network connection
    5 U-loop network connection
    6 N/C
    7 -48 VDC
    8 -48 VDC Return

    The ISDN cables can be silver satin patch cables (the kind that
    make 10Base-T Ethernet installers cringe). The S/T bus can also
    be silver satin but most installers use CAT 3 or CAT 5 with one
    drop per terminal equipment. It is true that only 4-wires are
    needed on the S/T bus but see below for optional power needs.

    21.3 ISDN S/T Bus (Point-to-Point)
    One logical terminal is on the S/T bus which can be 1km long.

    21.4 ISDN S/T Bus (Short Passive)
    Up to eight terminals on the S/T bus which can be within 100 to

    21.5 ISDN S/T Bus (Extended Passive)
    Up to eight terminals on the S/T bus which can be up to 500m.

    21.6 ISDN S/T Bus (NT1 Star)
    Up to eight terminals on the S/T bus which are wired from a
    central NT1 and can be up to 1km in length each.

    21.7 ISDN S/T Bus Pinout
    The S/T bus connects the NT1 with the terminal equipment. See
    section 10.0 for plug identification and pin numbering. Note,
    if power is not required an RJ11 (6-pin) plug could be used.
    Some NT1 devices have a switch to turn off power if it is not
    required by the terminal equipment. For safety reasons the
    power should not be put on the S/T bus if it is not required.
    Typically, ISDN PC cards do not require power from the S/T bus,
    but ISDN telephones do require power from the S/T bus. Check
    your vendor equipment specifications carefully.

    RJ45 Plug for ISDN S/T bus
    1 N/C
    2 N/C
    3 White/Green ..... Receive +
    4 Blue ............ Transmit+
    5 White/Blue ...... Transmit-
    6 Green ........... Receive -
    7 White/Brown ..... -48VDC (option)
    8 Brown ........... -48VDC Return (option)

    21.8 ISDN Cabling Guidelines
    The North American ISDN Users Forum (NIUF) has produced a document

    titled _ISDN Wiring and Powering Guidelines_ NIUF #433-94 which
    describes residence and small business ISDN cabling. See section
    30.0 for the NIUF document ordering address.


    Subject: 22.0 Testing Unshielded Twisted Pair Cables

    22.1 Testing UTP Introduction
    Many of the problems encountered in UTP cable plants are a result
    of miswired patch cables, jacks and crossconnects.

    Horizontal and riser distribution cables and patch cables are
    straight through end-to-end -- pin 1 at one end should be
    to pin 1 at the other. (Crossover patch cables are an exception,
    described later). Normally, jacks and crossconnects are designed
    that the installer always punches down the cable pairs in a
    order, from left to right: pair 1 (Blue), pair 2 (Orange), pair 3
    (Green) and pair 4 (Brown). The white striped lead is usually
    down first, followed by the solid color. The jack's internal
    connects each pair to the correct pins, according to the
    scheme for which the jack is designed: EIA-568A, 568B, USOC or
    whatever. (One source of problems is an installation in which USOC

    jacks are mixed with EIA-568A or 568B. Everything appears to be
    punched down correctly, but some cables work and others do not).

    22.2 Wiremap Tests
    Wiremap tests will check all lines in the cable for all of the
    following errors:

    Open: Lack of continuity between pins at both ends of
    the cable.
    Short: Two or more lines short-circuited together.
    Crossed pair: A pair is connected to different pins at each
    end (example: pair 1 is connected to pins 4&5
    at one end, and pins 1&2 at the other).
    Reversed pair: The two lines in a pair are connected to opposite

    pins at each end of the cable (example: the line
    on pin 1 is connected to pin 2 at the other end,
    the line on pin 2 is connected to line 1). Also
    called a polarity reversal or tip-and-ring reversal.
    Split pair: One line from each of two pairs is connected as
    it were a pair (example: the Blue and White-Orange
    lines are connected to pins 4&5, White-Blue and
    Orange to pins 3&6). The result is excessive Near
    End Crosstalk (NEXT), which wastes 10Base-T
    bandwidth and usually prevents 16 Mb/s token-ring
    from working at all.

    22.3 Length Tests
    Checking cable length is usually done using a time domain
    reflectometer (TDR), which transmits a pulse down the cable, and
    measures the elapsed time until it receives a reflection from the
    far end of the cable. Each type of cable transmits signals at
    something less than the speed of light. This factor is called the

    nominal velocity of propagation (NVP), expressed as a decimal
    fraction of the speed of light. (UTP has an NVP of approximately
    0.59-0.65). From the elapsed time and the NVP, the TDR calculates
    the cable's length. A TDR may be a special-purpose unit such as
    the Tektronix 1503, or may be built into a handheld cable tester.

    22.4 Testing for Impulse Noise
    The 10Base-T standard defines limits for the voltage and number of

    occurrences/minute of impulse noise occurring in several frequency

    ranges. Many of the handheld cable testers include the capability
    to test for this.

    22.5 Near-End Crosstalk (NEXT)
    What's NEXT, you ask? Imagine yourself speaking into a telephone.
    Normally, as you speak you can hear the person on the other end
    and also hear yourself through the handset. Imagine how it would
    sound if your voice was amplified so it was louder than the other
    person's. Each time you spoke you'd be deaf to anything coming
    the other end. A cable with inadequate immunity to NEXT couples so

    much of the signal being transmitted back onto the receive pair
    (or pairs) that incoming signals are unintelligible.

    Cable and connecting hardware installed using poor practices can
    their NEXT performance reduced by as much as a whole Category.

    22.6 Attenuation
    A signal traveling on a cable becomes weaker the further it
    Each interconnection also reduces its strength. At some point the
    signal becomes too weak for the network hardware to interpret
    Particularly at higher frequencies (10MHz and up) UTP cable
    signals much sooner than does co-axial or shielded twisted pair
    Knowing the attenuation (and NEXT) of a link allows you to
    whether it will function for a particular access method, and how
    margin is available to accommodate increased losses due to
    changes, aging, etc.

    Forthcoming updates to cabling standards call for a number of new
    tests which will add to this list.


    Subject: 23.0 - 29.0 Not Used (Blank)

    These sections are blank for future topics.


    Subject: 30.0 Sources of Additional Information

    Addr: Harrisburg, PA 17105-3608
    Tel: 1-800-722-1111
    1-800-245-4356 (Faxback service, USA)
    (905) 470-4425 Canada
    (617) 270-3774 (Faxback service, Canada)

    (An international cable products distributor)
    see _Anixter 199x Cabling Systems Catalog_
    Addr: Anixter, Inc
    4711 Golf Road
    Skokie, IL 60076
    Tel: (708) 677-2600
    1-800-323-8167 USA
    1-800-361-0250 Canada
    32-3-457-3570 Europe
    44-81-561-8118 UK
    65-756-7011 Singapore

    Addr: American National Standards Institute
    11 W. 42nd St, 13th floor
    New York, NY 10036
    Tel: (212) 642-4900

    AT&T Canada:
    Addr: Network Cables Div
    1255 route Transcanadienne
    Dorval, QC H3P 2V4
    Tel: (514) 421-8213
    Fax: (514) 421-8224

    AT&T documents:
    Addr: AT&T Customer Information Center
    Order Entry
    2855 N. Franklin Road
    Indianapolis, IN 46219 USA
    Tel: (800) 432-6600 (USA)
    (800) 255-1242 (CDN)
    (317) 352-8557 (International)
    Fax: (317) 352-8484

    Belden Wire & Cable:
    Addr: POB 1980
    Richmond, IN 47375
    Tel: (317) 983-5200

    Bell Canada:
    Addr: Bell Canada
    Building Network Design
    Floor 2, 2 Fieldway Road
    Etobicoke, Ontario
    Canada M8Z 3L2
    Tel: (416) 234-4223
    Fax: (416) 236-3033

    Bell Communications Research (Bellcore):
    Addr: Customer Service
    60 New England Ave
    Piscataway, NJ 08854
    Tel: (800) 521-2673
    Fax: (908) 336-2559

    Berk-Tek: (copper & f/o cable)
    Addr: 312 White Oak Rd
    New Holland, PA 17557
    Tel: (717) 354-6200, 1-800-BERK-TEK
    Fax: (717) 354-7944

    BICSI: A telecommunications cabling professional association.
    Offers education, and administers the RCDD (Registered
    Communications Distribution Designer) certification.
    Addr: Building Industries Consulting Service International
    10500 University Center Drive, Ste 100
    Tampa, FL 33612-6415
    Tel: (813) 979-1991, 1-800-BICSI-05
    Fax: (813) 971-4311

    Black Box Catalog: The Source for Connectivity (r)
    Addr: Black Box Inc
    P.O. Box 12800
    Pittsburgh, PA 15241
    Tel: 1-800-552-6816 USA
    (412) 746-5500 Tech Support USA
    (416) 736-8013 Tech Support Canada

    Addr: Canadian Automated Buildings Association
    M-20, 1200 Montreal Rd
    Ottawa, ON K1A 0R6
    Tel: (613) 990-7407
    Fax: (613) 954-5984

    CableTalk: (racks & physical cable management)
    Addr: 18 Chelsea Lane
    Brampton, ON L6T 3Y4
    Tel: (800) 267-7282
    (905) 791-9123
    Fax: (905) 791-9126

    Cabling Business:
    Addr: Cabling Business Magazine
    12035 Shiloh Road, Ste 350
    Dallas, TX 75228
    Tel: (214) 328-1717
    Fax: (214) 319-6077

    Cabling Installation & Maintenance Magazine:
    Addr: Cabling Installation & Maintenance
    Editorial Offices
    One Technology Park Dr
    POB 992
    Westford, MA 01886
    Tel: (508) 692-0700
    Tel: (918) 832-9349
    Fax: (918) 832-9295

    CCITT: See ITU

    Comm/Scope Inc.
    Addr: POB 1729,
    Hickory, NC 28603
    Tel: (800) 982-1708 (USA)
    (704) 324-2200
    Fax: (704) 328-3400

    Addr: Corning Optical Fiber Information Center
    Guidelines - publication/newsletter on fiber technology
    FiberFax-on-Demand: ???

    Addr: Canadian Standards Association
    178 Rexdale Blvd
    Rexdale, Ont
    Canada M9W 1R3
    Tel: (416) 747-4000, Documents Orders: (416) 747-4044
    Fax: (416) 747-2475

    Addr: EIA Standards Sales Office
    2001 Pennsylvania Ave., N.W.
    Washington, DC 20006
    Tel: (202) 457-4966

    Addr: Global Engineering Documents
    1990 M Street W, Suite 400
    Washington, DC 20036
    Tel: (800) 854-7179 (CDN/USA)
    (202) 429-2860 (International)
    (714) 261-1455 (International)
    Fax: (317) 352-8484

    Global Engineering Documents (West Coast)
    2805 McGaw Ave.
    Irvine, CA 92714

    (An international cable products distributor)
    Tel: (519) 576-4050 in Ontario
    Fax: (519) 576-2402

    Addr: Hubbell Premise Wiring Inc.
    14 Lords Hill Rd
    Stonington, CT 06378
    Tel: (203) 535-8326
    Fax: (203) 535-8328

    Addr: International Electrotechnical Commission
    rue de Varembre, Case Postale 131,3
    Geneva 20, Switzerland

    Addr: International Organization for Standardization
    1, rue de Varembre, Case Postale 56
    Geneva 20, Switzerland
    Tel: +41 22 34 12 40

    (Previously called CCITT)
    Addr: International Telephone Union
    Place des Nations
    Geneva 20, Switzerland

    (Cable and Equipment Suplier)
    Addr: Mod-Tap
    285 Ayer Rd, P.O. Box 706
    Harvard, MA 01451
    Tel: (508) 772-5630
    Fax: (508) 772-2011

    NFPA (US National Electrical Code (NEC) and other docs):
    Addr: National Fire Protection Association
    One Battery March Park, P.O. Box 9146
    Quincy, MA 02269-9959
    Tel: (800) 344-3555
    Fax: (617) 984-7057

    Addr: U.S. Dept. of Commerce
    National Institute of Standards and Technology
    Technology Building 225
    Gaithersburg, MD 20899

    Addr: North American ISDN Users Forum
    NIUF Secretariat
    National Institute of Standards and Technology
    Bldg 223, Room B364
    Gaithersburg, MD 20899
    Tel: (301) 975-2937
    Fax: (301) 926-9675

    Northern Telecom (cable and physical network products):
    Addr: Business Networks Div.
    105 Boulevard Laurentien
    St. Laurent, QC H4N 2M3
    Tel: (514) 744-8693, 1-800-262-9334
    Fax: (514) 744-8644

    Addr: U.S. Dept. of Commerce
    National Technical Information Service
    5285 Port Royal Rd
    Springfield, VA 22161
    Tel: (703) 487-4650
    (800) 336-4700 (rush orders)
    Fax: (703) 321-8547

    NRC of Canada:
    Addr: Client Services
    Institute for Research in Construction
    National Research Council of Canada
    Ottawa, ON K1A 0R6
    Tel: (613) 993-2463
    Fax: (613) 952-7673

    Addr: 595 Greenhaven Rd
    Pawcatuck, CT 06379
    Tel: (203) 599-1760
    Fax: (203) 599-1774


    Saunders Telecom: (racks, tray and accessories)
    Addr: 8520 Wellsford Place
    Santa Fe Springs, CA
    Tel: (800) 927-3595
    Fax: (310) 698-6510

    Addr: Standards Council of Canada
    1200-45 O/Connor St
    Ottawa, Ont Canada K1P 6N7
    Tel: (613) 238-3222
    Fax: (613) 995-4564

    Addr: 489 Siecor Park, POB 489
    Hickory, NC 28603-0489
    Tel: (704) 327-5000
    Fax: (704) 327-5973

    The Siemon Co (Cabling System Supplier)
    Addr: 76 Westbury Park Rd
    Watertown, CT 06795
    Tel: (203) 274-2523
    Fax: (203) 945-4225

    Addr: Telecommunications Industries Association (TIA)
    2500 Wilson Boulevard, Suite 300,
    Arlington, VA 22201
    Tel: (703) 907-7700
    Fax: (703) 907-7727

    Underwriters Labs (UL) documents:
    Addr: Underwriters Labs Inc
    333 Pfingsten Road,
    Northbrook, Illinois 60062-2096 USA
    Tel: (800) 676-9473 (from CDN/USA East coast)
    (800) 786-9473 (from CDN/USA West coast)
    (708) 272-8800 (International)
    Fax: (708) 272-8129
    MCI Mail: 254-3343

    --------------------------END OF CABLING FAQ---------------------------


    Brad Reese
    BradReese.Com Cisco Certified Network Engineer Jobs
    United Kingdom: 44-20-70784294
    U.S. Toll Free: 877-549-2680
    International: 828-277-7272
    Fax: 775-254-3558
    BradReeseCom, Feb 25, 2005
    1. Advertisements

  3. In article <>,
    <> wrote:
    :I guess the answer is
    :2.that the white-orange/orange pair is attached first

    :2. To ensure reliable LAN communications, what should a technician be
    :looking for when attaching connectors to the ends of UTP cable?

    : that the white-orange/orange pair is attached first

    What use is that? You aren't going to be putting a signal on
    it until all the pairs are attached.

    : that the wire pairs remain twisted as much as possible

    Why would you want ethernet wires to be twisted?

    : that one end of the shield is properly ground but not the other

    In the RF industry, that configuration is better know as
    "an antenna".

    : that 50 ohm termination resistors are on both ends

    Is ethernet wire terminated? What do resistors do for you?

    "No one has the right to destroy another person's belief by
    demanding empirical evidence." -- Ann Landers
    Walter Roberson, Feb 25, 2005
  4. My response would be:

    1." the highest frequencies that the cable is rated to support". The
    lowest frequency any cable can support is DC, so at that freq. all you
    are measuring is resistance. The 20hz to 20khz is just for checking
    freq response of audio equipment. Using 100ghz on cat-5 would show
    mucho loss. Each version of cable (Cat-5, Cat-5e, Cat-6, etc.) has a
    different high end. Measuring loss up to that limit is what you are
    interested in.

    2. Colors don't mean a thing. As long as you have the same colors
    (and pairs) on the same pins at each end, it will work.

    Answer: the wires must remain twisted as much as possible. It's the
    twisting of the pairs that helps the most in preventing cross-talk
    from one pair to another.


    On 24 Feb 2005 15:14:26 -0800, ""
    <> wrote:

    >I guess the answer is
    >1.the lowest frequencies that the cable is rated to support
    >2.that the white-orange/orange pair is attached first
    >what do you guy think?
    >1. Which frequencies are used by a cable tester to measure attenuation?
    > the lowest frequencies that the cable is rated to support
    > the highest frequencies that the cable is rated to support
    > frequencies from 20 Hz to 20 kHz in 20 Hz increments
    > 10 kHz and 100 GHz
    >2. To ensure reliable LAN communications, what should a technician be
    >looking for when attaching connectors to the ends of UTP cable?
    > that the white-orange/orange pair is attached first
    > that the wire pairs remain twisted as much as possible
    > that one end of the shield is properly ground but not the other
    > that 50 ohm termination resistors are on both ends
    Bob Peticolas, Feb 25, 2005
  5. Guest

    1. Not sure. Makes sense though.
    2. Actually it does matter. What you said is true, but the pairs have
    different twists per foot brown being the least twisted. At higher
    speeds this can affect signals.
    , Feb 26, 2005
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