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 ( email@example.com) 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 rtfm.mit.edu approval, cable testing 950124 - added bending radius specs, ISDN cabling 950110 - added headers required for rtfm.mit 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.
THIS DOCUMENT IS A GUIDELINE ONLY -- SEEK PROFESSIONAL ADVICE, CHECK LOCAL BUILDING CODES AND APPLICABLE STANDARDS.0.4 Acknowledgments
firstname.lastname@example.org (Bill Hughes) email@example.com (Evan Gamblin) snipped-for-privacy@kn.PacBell.COM (John Lundgren) firstname.lastname@example.org (Mike Barker) email@example.com.COM (Henriecus Koeman)
TABLE OF CONTENTS 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 56810.0 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 toxic combustion products produced. All they cover is performance on a flamespread test.
THIS DOCUMENT IS A GUIDELINE ONLY -- SEEK PROFESSIONAL ADVICE, CHECK LOCAL BUILDING CODES AND APPLICABLE STANDARDS.
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 Communication 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.
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 indoors 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 DEC MMJ 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 Cables_ EIA/TIA Tech Sys Bulletin TSB-36, Nov 1991 [Transmission Characteristics of Category 3-5 UTP cables]
_Additional Transmission Specifications for UTP Connecting Hardware_ 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 cable]
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 standard]
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, mechanical 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), 1994
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., 1980 [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 Brown9.2 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 Brown9.3 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, 7-8) 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 Cabling12.1 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 812.2 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- 212.3 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------- 612.4 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 UTP]
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 Equipment15.1 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 pairs, 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, reversed pairs, crossed pairs and split pairs.
A least-cost wiremap type tester that detects split pairs correctly (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 ranges. 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 communication 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 Layout17.1 Wiring Layout
......Wiring Closet.............. ....User Work Area.... [HUB][PANEL]+=====+[BLOCK]+==============+[WALL][STATION]
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 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
Source: Integrated Building Distribution Network (IBDN) User Manual - Northern Telecom, doc # IBDN-UM-9105, 1991.
The EIA/TIA working group revising the EIA-569 standard is using the 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 minimum bend radius for UTP is 4 x cable outside diameter, about one inch. For multipair cables the minimum bending radius is 10 x outside diameter.
SP-2840A gives minimum bend radii for Type 1A Shielded Twisted Pair (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 x diameter. SP-2840A states that no f/o cable will be bent on a radius 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 radii. 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 Cable20.1 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 km. 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 construction is a larger bending radius. Gel-filled cable requires the installer 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 fiber. Results in a smaller cable diameter with a smaller bending radius. Typical applications are patch cords and local area network connections. At least one mfr. produces this type of cable for inside/outside use. 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 connector. 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 length of a cable, and detect any flaws in it. Can also be used to measure 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 line.
Fiber Optic Testing, standards: see EIA-455-171 (FOTP-171), EIA 526-14.
Subject: 21.0 ISDN Cabling21.1 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/C21.2 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 200m. 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 Cables22.1 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 wired straight through end-to-end -- pin 1 at one end should be connected to pin 1 at the other. (Crossover patch cables are an exception, as described later). Normally, jacks and crossconnects are designed so that the installer always punches down the cable pairs in a standard order, from left to right: pair 1 (Blue), pair 2 (Orange), pair 3 (Green) and pair 4 (Brown). The white striped lead is usually punched down first, followed by the solid color. The jack's internal wiring connects each pair to the correct pins, according to the assignment 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 if 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 from 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 have 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 travels. Each interconnection also reduces its strength. At some point the signal becomes too weak for the network hardware to interpret reliably. Particularly at higher frequencies (10MHz and up) UTP cable attenuates signals much sooner than does co-axial or shielded twisted pair cable. Knowing the attenuation (and NEXT) of a link allows you to determine whether it will function for a particular access method, and how much margin is available to accommodate increased losses due to temperature 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
AMP 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)
Anixter (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
ANSI: 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
Blackbox 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 Inet: firstname.lastname@example.org
CABA: 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 Subscriptions: 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
Corning: Addr: Corning Optical Fiber Information Center 1-800-525-2524 Guidelines - publication/newsletter on fiber technology FiberFax-on-Demand: ??? Inet: email@example.com
CSA: 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
EIA: Addr: EIA Standards Sales Office 2001 Pennsylvania Ave., N.W. Washington, DC 20006 Tel: (202) 457-4966
GED: 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 800-854-7179
Graybar: (An international cable products distributor) 1-800-825-5517 Tel: (519) 576-4050 in Ontario Fax: (519) 576-2402
Hubbell: Addr: Hubbell Premise Wiring Inc. 14 Lords Hill Rd Stonington, CT 06378 Tel: (203) 535-8326 Fax: (203) 535-8328
IEC: Addr: International Electrotechnical Commission rue de Varembre, Case Postale 131,3 CH-1211 Geneva 20, Switzerland
ISO: Addr: International Organization for Standardization 1, rue de Varembre, Case Postale 56 CH-1211 Geneva 20, Switzerland Tel: +41 22 34 12 40
ITU: (Previously called CCITT) Addr: International Telephone Union Place des Nations CH-1211 Geneva 20, Switzerland
MOD-TAP: (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
NIST: Addr: U.S. Dept. of Commerce National Institute of Standards and Technology Technology Building 225 Gaithersburg, MD 20899 NIUF: 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 Internet: firstname.lastname@example.org
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
NTIS: 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
Ortronics: Addr: 595 Greenhaven Rd Pawcatuck, CT 06379 Tel: (203) 599-1760 Fax: (203) 599-1774
RCDD: See BICSI
Saunders Telecom: (racks, tray and accessories) Addr: 8520 Wellsford Place Santa Fe Springs, CA Tel: (800) 927-3595 Fax: (310) 698-6510
SCC: Addr: Standards Council of Canada 1200-45 O/Connor St Ottawa, Ont Canada K1P 6N7 Tel: (613) 238-3222 Fax: (613) 995-4564
Siecor: Addr: 489 Siecor Park, POB 489 Hickory, NC 28603-0489 Tel: (704) 327-5000 Fax: (704) 327-5973
Siemon: The Siemon Co (Cabling System Supplier) Addr: 76 Westbury Park Rd Watertown, CT 06795 Tel: (203) 274-2523 Fax: (203) 945-4225
TIA: Addr: Telecommunications Industries Association (TIA) 2500 Wilson Boulevard, Suite 300, Arlington, VA 22201 Tel: (703) 907-7700 Fax: (703) 907-7727
UL: 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 Inet: email@example.com MCI Mail: 254-3343
--------------------------END OF CABLING FAQ---------------------------