Cabling Standard - TIA 568 B.1 - Addendum 7 - Final

TIA
STANDARD


ANSI/TIA-568-B.1-7-2006
Approved: January 13, 2006

Commercial Building Telecommunications
Cabling Standard

Part 1 - General Requirements

Addendum 7 – Guidelines for Maintaining
Polarity Using Array Connectors



TIA-568-B.1-7
(Addendum No.7 to TIA-568-B.1)

January 2006



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TIA-568-B.1-7
ii
Guidelines for Maintaining Polarity Using Array Connectors,
Addendum 7 to ANSI/TIA/EIA/568B.1

Table of Contents

FOREWORD ...................................................................................................................................iv

1

INTRODUCTION ..................................................................................................................... 1

2

SCOPE .................................................................................................................................... 2

3

CONNECTIVITY METHODS FOR ESTABLISHING POLARITY............................................ 2

3.1

General................................................................................................................................ 2

3.1.1

Descriptions................................................................................................................. 2

3.2

Connectivity Method A......................................................................................................... 3

3.2.1

Connectivity Method A for Duplex Signals .................................................................. 3

3.2.2

Connectivity Method A for Parallel Signals.................................................................. 5

3.3

Connectivity Method B......................................................................................................... 7

3.3.1

Connectivity Method B for Duplex Signals .................................................................. 7

3.3.2

Connectivity Method B for Parallel Signals.................................................................. 9

3.4

Connectivity Method C ...................................................................................................... 11

3.4.1

Connectivity Method C for Duplex Signals................................................................ 11

4

GUIDELINES FOR CONNECTIVITY COMPONENTS ......................................................... 13

4.1

General.............................................................................................................................. 13

4.2

Components for Connectivity Method A............................................................................ 14

4.2.1

Type-A Array Connector Cables and Patch Cords.................................................... 14

4.2.2

Type-A Array Adapters .............................................................................................. 14

4.2.3

Transitions ................................................................................................................. 15

4.2.4

A-to-B patch cords..................................................................................................... 16

4.2.5

A-to-A Patch cords..................................................................................................... 16

4.3

Components for Connectivity Method B............................................................................ 17

4.3.1

Type-B Array Connector Cables and Patch Cords.................................................... 17

4.3.2

Type-B Array Adapters .............................................................................................. 17

4.3.3

Transitions ................................................................................................................. 17

4.3.4

A-to-B patch cords..................................................................................................... 17

4.4

Components for Connectivity Method C............................................................................ 18

4.4.1

Type-C Array Connector Cables ............................................................................... 18

4.4.2

Type-A Array Adapters .............................................................................................. 18

4.4.3

Transitions ................................................................................................................. 18

4.4.4

A-to-B patch cords..................................................................................................... 18

ANNEX A (INFORMATIVE) References ....................................................................................... 19



TIA-568-B.1-7
iii
List of Figures

Figure 1: Connectivity Method A for Duplex Signals.........................................................4

Figure 2: Connectivity Method A for Parallel Signals........................................................6

Figure 3: Connectivity Method B for Duplex Signals.........................................................8

Figure 4: Connectivity Method B for Parallel Signals......................................................10

Figure 5: Connectivity Method C for Duplex Signals.......................................................12

Figure 6: Type-A Array Connector Cable or Patch Cord (key-up to key-down)..............14

Figure 7: Transition.........................................................................................................15

Figure 8: A-to-B Duplex Patch Cord................................................................................16

Figure 9: A-to-A Duplex Patch Cord................................................................................16

Figure 10: Type-B Array Connector Cable or Patch Cord (key-up to key-up).................17

Figure 11: Type C Array Connector Cable (pair-wise flipped, key-up to key-down) .......18


List of tables

Table 1: Summary of Components Used for Duplex Signals..........................................13

Table 2: Summary of Components Used for Parallel Signals.........................................13



TIA-568-B.1-7
iv
FOREWORD

(This foreword is not part of this Standard)

After ANSI/TIA/EIA-568-B.1 was approved for publication, it was realized that there was
a need to explain and illustrate the concept of maintaining optical fiber polarity using
array connectors. The TIA TR-42 Engineering Committee on Premises
Telecommunications Cabling Infrastructure accepted the task and assigned it to the TR-
42.8 Subcommittee, Telecommunications Optical Fiber Cabling Systems. The TR-42.8
Subcommittee cooperated with the TR-42.1 Subcommittee on Commercial Building
Cabling, which is related to this activity, in preparing this document.

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The viewpoint expressed at the time that this Telecommunication Systems Bulletin was
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Users are encouraged to verify that they have the latest revision of the standard.


TIA-568-B.1-7
1
1 INTRODUCTION

To support bi-directional communication systems that use separate optical fibers in each
direction, the cabling system must provide correct signal polarity so that the transmitter on one
end of the channel will connect to the receiver on the other end. Maintaining the correct
transmit-to-receive polarity throughout the cabling system is critical for system operation.
Following certain cable polarity guidelines when installing the cabling system will simplify
channel connectivity.

Correct polarity is administered according to the requirements of the depicted methods.
Intermixing the components of these methods may result in incorrect polarity.

The increasing use of optical connectivity in data communications networks (particularly in
areas of highly concentrated equipment, such as data centers) is driving the need for more
compact forms of connectivity. Array connectors are one way of meeting this need. Since the
polarity requirements for array connectors extend beyond the commonly deployed duplex (A-B)

polarity, additional guidance is provided in this addendum for maintaining polarity of networks
utilizing array connectors.

For illustrative purposes, the figures throughout this document depict the MPO array connector
and 568SC duplex connector. Other connector types are permitted, provided the fiber ordering
arrangement is maintained relative to the plug’s keying features, as shown in the figures.

The figures in this document show connectors labeled with fiber position numbers. This is done
for reference only; it is not a requirement of this standard that connectors be labeled with a fiber
number.


TIA-568-B.1-7
2
2 SCOPE

This Standard provides guidelines for establishing transmit-to-receive polarity using array
connectors. The methods presented in this document provide different options for implementing
polarity. Once a method is selected the details in that method shall be followed.

3 CONNECTIVITY METHODS FOR ESTABLISHING POLARITY

3.1 General

All connectivity methods have the same goal: to create an optical path from the transmit port of
one device to the receive port of another device. Different methods to accomplish this goal may
be implemented; however these different methods may not be interoperable. It is recommended
that a method be selected in advance and maintained consistently throughout an installation.
While many methods are available to establish polarity, this Standard outlines sample methods
that may be employed. For convenience, these sample methods are referred to as Methods A,

B, and C. No preference or priority is implied by this notation.

When mating connectors that use alignment pins (such as the MPO and MT-RJ) it is critical that
one plug is pinned and the other plug is unpinned. The pinned connector is typically located
inside the panel. That is, the connector that stays in place is pinned; the connector that is
frequently removed & handled is unpinned. As MT-RJ or MPO transceivers typically have pins,
this convention leads to the following implementation on initial build out:

• Patch cords from transceiver to panel are typically unpinned on both ends.
• Transitions (mounted behind the panel) are typically pinned.
• Cables from rack to rack are typically unpinned on both ends.

Array connectors can be flat or angle polished. Flat-polished connectors do not optically mate
with angle-polished connectors.

3.1.1 Descriptions

A-to-B patch cord: A duplex patch cord that connects position A on one end of the patch cord
to position B on the other end of the patch cord. See section 4.2.4.

A-to-A patch cord: A duplex patch cord that connects position A on one end of the patch cord
to position A on the other end of the patch cord. See section 4.2.5.

Array Connector: An optical fiber connector containing a single ferrule with multiple terminated
fibers arranged in a line or a series of lines.

Transition: An assembly of optical fibers and connectors, with an array connector on one end
and simplex or duplex connectors on other end.

TIA-568-B.1-7
3
3.2 Connectivity Method A

3.2.1 Connectivity Method A for Duplex Signals

Implementation of Connectivity Method A for duplex signals is shown in Figure 1.

When connecting multiple duplex optical transceiver ports, the Type-A backbone (composed of
one or many Type-A array connector cables mated in Type-A adapters) is connected on each
end to a transition. On one end of the optical link, A-to-B patch cords are used to connect ports
on the transition to their respective duplex transceiver ports. On the other end of the optical link,
A-to-A patch cords are used to connect ports on the transition to their respective duplex
transceiver ports. In each optical path there shall be one and only one A-to-A patch cord.

Guidelines for the construction of the cabling components used to implement Method A are
given in Section 4.2.




TIA-568-B.1-7
4
Figure 1: Connectivity Method A for Duplex Signals
NOTE
1. For ease of illustration the Type-A cable is shown with a twist. This is the same cable construction shown in Figure 6.
Example Optical Path
A-to-B Patch Cord
Type-A Array
Connector Cable

A-to-A Patch Cord