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).

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 flame spread 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 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.

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

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)


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

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.

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

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]

Standard EIA/TIA 568

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

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

Pin Wire Color
=== ==========

 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
\----- pair4 \--R4 8 Brown

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

 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

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

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

   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

    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

 ......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)

  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 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.

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.

Fiber Optic Cable

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.

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).

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.

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.

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.

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.


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.

ISDN Cabling

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.

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

ISDN S/T Bus (Short Passive)
Up to eight terminals on the S/T bus which can be within 100 to 200m.

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

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.

ISDN S/T Bus Pinout
The S/T bus connects the NT1 with the terminal equipment. 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)
 

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