Abstract

The present document describes the principles for powering of telecommunications equipment in access network and contains requirements for the powering systems, laying down:
- the characteristics of the input and output interfaces of the power units;
- the power back-up conditions for TE including a power unit;
- the management data, necessary to guarantee the availability of the service and to ensure the maintenance of the power units.
The present document takes into account the characteristics of access network equipment for which the limits of responsibility in the installation or design of the power plants are very different than for equipment of telecom centre: it goes from "complete integration of the power plant in the TE" till "remote power feeding from a distant power plant". The present document applies for the powering of all equipment of the access network (copper, fiber or radio networks) located outside telecommunications centres. The access network is defined as the part of the telecommunications network, which is comprised between the customer terminal installation and the first exchange (switching unit). The customer terminal and the switching unit are excluded of the application field of the present document.

Status
Published
Publication Date
31-Jan-2006
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Feb-2006
Due Date
01-Feb-2006
Completion Date
01-Feb-2006

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SIST EN 302 099 V1.1.1:2006

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SIST EN 302 099 V1.1.1:2006 specifies the principles for powering telecommunications equipment in the access network. The standard covers power interfaces, back-up conditions, and the management data needed to keep service available and to support maintenance. It is written for designers, operators, installers, and others who need to choose or verify how access-network equipment is powered.

What does SIST EN 302 099 V1.1.1:2006 specify?

SIST EN 302 099 V1.1.1:2006 applies to powering of access-network equipment located outside telecommunications centres. It covers copper, fiber, and radio access networks, and it excludes the customer terminal and the first switching unit.

The document is organized around powering configurations and their practical consequences. Clauses 4 to 11 cover powering architectures, the effect of technology on the powering strategy, local and remote powering requirements, power back-up, power management, safety, EMC, protection, bonding and earthing, and environmental conditions.

AnnexWhat it covers
Annex ABattery sizing for back-up power
Annex BBibliography

What are the key requirements of SIST EN 302 099 V1.1.1:2006?

SIST EN 302 099 V1.1.1:2006 is built around the idea that the location of the mains connection and the location of back-up power drive the whole powering design. In practice, that means the operator or manufacturer must first decide whether the equipment is centrally powered, cluster powered, or locally powered, and then match the interface and back-up arrangement to that choice.

Powering architectures and where they apply

Clause 4 distinguishes centralized powering, cluster powering, and local powering. Centralized powering feeds access-network equipment from a telecommunications centre; cluster powering feeds a group of equipment from a remote source outside the centre; local powering uses a power unit at the same location as the equipment.

Clause 5 links those architectures to network technology. For copper access, centralized powering is suitable when power consumption is low enough, local powering is used when demand is higher, and a local battery can supplement centralized powering during traffic peaks. For fiber and radio access, local powering is generally the normal solution, while cluster powering can be cost-effective when many units are concentrated in one area. For hybrid networks, the same basic logic applies, and customer-home equipment is powered locally.

Local powering requirements

Clause 6 sets the local-power interface conditions. A telecommunications equipment unit with its own power plant uses a nominal 230 V, 50 Hz input, and continuity of service comes from a battery back-up unit. Where a Local Power Unit (LPU) supplies -48 V dc, the input characteristics have to comply with EN 300 132-2.

Clause 6 also allows local power at other dc voltages, but that must be stated in the individual technical specification for the equipment. For equipment powered from a nominal 230 V, 50 Hz local power unit, the LPU may be an uninterruptible power supply. In practice, these clauses tell the designer which voltage and back-up arrangement must be specified at the interface between the power source and the telecom equipment.

Remote powering requirements

Clause 7 defines the input and output conditions for remote powering. In centralized powering, the Remote Power Unit (RPU) is fed from the telecommunications-centre power plant, typically at -48 V dc. In cluster powering, the RPU input is 230 V, 50 Hz.

The standard recognizes two remote-powering modes at the RPU output: voltage mode with an RFT-V circuit and current mode with an RFT-C circuit. For voltage mode, the receiver must accept an input range from the nominal output voltage down to half that value. In practice, this matters because line length, line resistance, and the number of receivers affect the voltage that reaches the equipment.

Back-up and battery sizing

Clause 8 requires a back-up system, normally batteries, to keep telephone service running during mains outage or failure of upstream power equipment. For centralized remote powering, the text also allows a standby source such as a turbine or motor-driven generator to supplement back-up.

Annex A gives the battery-sizing method. It ties back-up power to the equipment’s base power, traffic-dependent power, subscriber count, and the service conditions during discharge. It also requires the battery capacity to cover ageing and minimum operating temperature, and it addresses valve regulated lead-acid batteries and end-of-life testing. For a user, this means the battery cannot be sized only for a best-case site - it must be justified for the real load and operating environment.

Power management, alarms, and maintenance

Clause 9 requires the operator to know the status of the power sub-assemblies so maintenance can be planned and service availability protected. The standard groups failure events into three alarm categories, ranging from events that normally do not need immediate intervention to failures that need urgent action.

The alarm duties differ by architecture. Centralized powering leaves power management to the source side. Local powering and cluster powering require the telecom equipment to provide alarm loops, forward alarms from the LPU or RPU, and in some cases monitor the failure events directly. In practical terms, the operator needs enough alarm visibility to know when power conversion, protection devices, monitoring units, or battery conditions need attention.

Safety, EMC, protection, earthing, and environment

Clause 10 points to external standards for product safety and interface classification. It also requires compliance with relevant EMC standards. For mains-fed or UPS-fed equipment, the design has to take overvoltage categories into account, and bonding and earthing have to follow the applicable telecom-centre, customer-premises, remote-site, or national rules.

Clause 11 links the equipment to ETSI environmental classifications for storage and stationary use at weatherprotected, non-weatherprotected, and underground locations. This matters because access-network equipment may be installed in cabinets, buildings, homes, poles, or manholes, and the environment can vary widely from site to site.

What terms does SIST EN 302 099 V1.1.1:2006 define?

  • Access network - The part of a telecommunications network between the customer terminal installation and the first switching unit.
  • Local powering - A powering principle where a telecommunication equipment unit is supplied by a dedicated power unit at the same location.
  • Remote powering - A powering principle where a telecommunication equipment unit is supplied from a remote power circuit.
  • Remote Feeding Telecommunication (RFT) circuit - A secondary circuit intended to supply or receive dc power via a telecommunication network at voltages at or above TNV limits.
  • RFT-C circuit - An RFT circuit designed so that current stays within defined limits under normal and single-fault conditions.
  • RFT-V circuit - An RFT circuit designed so that voltage and accessible contact area stay limited under normal and single-fault conditions.
  • Remote Power Unit (RPU) - A power unit that feeds distant telecommunications equipment and is connected to mains or to a centralized power plant.
  • Local Power Unit (LPU) - A power supply unit that feeds telecommunications equipment at the same location.

Who uses SIST EN 302 099 V1.1.1:2006?

Telecommunications operators use SIST EN 302 099 V1.1.1:2006 to specify how access-network sites are powered and how alarms are reported for maintenance. Equipment manufacturers and system integrators use it to design the input and output interfaces, backup arrangements, and management functions of power units and telecom equipment.

Installers and site engineers use it when placing equipment in buildings, cabinets, manholes, customer premises, or remote sites, because the standard connects the powering choice to earthing, protection, and environmental conditions. Quality managers and buyers use it to check that a proposed access-network power arrangement matches the intended architecture, voltage interface, and backup strategy.

Which standards are used with SIST EN 302 099 V1.1.1:2006?

  • ETSI EN 300 132-2 - Defines the -48 V dc power supply interface at telecom-equipment input.
  • ETSI ETS 300 132-1 - Defines the ac interface derived from dc sources and is used for the interface referenced in telecom-centre powering.
  • CENELEC EN 60950-1 - Provides general safety requirements and the reference for SELV, TNV, primary circuit, secondary circuit, and hazardous voltage.
  • IEC 60950-21 - Covers safety of remote power feeding and is used for RFT-C and RFT-V interface categories.
  • CENELEC HD 472 S1 - Gives nominal voltages for low-voltage public electricity supply systems.
  • CENELEC HD 625.1 - Provides insulation coordination principles and tests for low-voltage systems.
  • CENELEC EN 50310 - Covers equipotential bonding and earthing in buildings with information technology equipment.
  • CENELEC EN 60896-2 - Sets requirements and test methods for valve regulated stationary lead-acid batteries.
  • ETSI EN 300 019-1-1, EN 300 019-1-3, ETS 300 019-1-4, EN 300 019-1-8 - Define environmental condition classes for storage, weatherprotected, non-weatherprotected, and underground use.
  • ETSI EN 300 253 - Covers earthing and bonding inside telecommunications centres.
  • ITU-T Recommendation K.35 - Covers bonding configurations and earthing at remote electronic sites.
  • ETSI EG 201 212 - Classifies interfaces for equipment connected to telecommunication networks.
  • ITU-T Recommendation K.45 - Addresses resistibility of access-network equipment to overvoltages and overcurrents.

What does the SIST EN 302 099 V1.1.1:2006 document contain?

SIST EN 302 099 V1.1.1:2006 includes configuration figures for centralized, cluster, and local powering, plus a technology figure that contrasts copper, optical, hybrid, and radio access networks. It also includes tables for alarm categories, management duties, interface safety categories, and example environmental classes.

Annex A gives the battery-sizing method for telephone-service back-up, including autonomy, ageing, operating temperature, valve regulated lead-acid batteries, and end-of-service-life testing. Annex B is a bibliography.

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Frequently Asked Questions

SIST EN 302 099 V1.1.1:2006 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Environmental Engineering (EE); Powering of equipment in access network". This standard covers: The present document describes the principles for powering of telecommunications equipment in access network and contains requirements for the powering systems, laying down: - the characteristics of the input and output interfaces of the power units; - the power back-up conditions for TE including a power unit; - the management data, necessary to guarantee the availability of the service and to ensure the maintenance of the power units. The present document takes into account the characteristics of access network equipment for which the limits of responsibility in the installation or design of the power plants are very different than for equipment of telecom centre: it goes from "complete integration of the power plant in the TE" till "remote power feeding from a distant power plant". The present document applies for the powering of all equipment of the access network (copper, fiber or radio networks) located outside telecommunications centres. The access network is defined as the part of the telecommunications network, which is comprised between the customer terminal installation and the first exchange (switching unit). The customer terminal and the switching unit are excluded of the application field of the present document.

The present document describes the principles for powering of telecommunications equipment in access network and contains requirements for the powering systems, laying down: - the characteristics of the input and output interfaces of the power units; - the power back-up conditions for TE including a power unit; - the management data, necessary to guarantee the availability of the service and to ensure the maintenance of the power units. The present document takes into account the characteristics of access network equipment for which the limits of responsibility in the installation or design of the power plants are very different than for equipment of telecom centre: it goes from "complete integration of the power plant in the TE" till "remote power feeding from a distant power plant". The present document applies for the powering of all equipment of the access network (copper, fiber or radio networks) located outside telecommunications centres. The access network is defined as the part of the telecommunications network, which is comprised between the customer terminal installation and the first exchange (switching unit). The customer terminal and the switching unit are excluded of the application field of the present document.

SIST EN 302 099 V1.1.1:2006 is classified under the following ICS (International Classification for Standards) categories: 19.040 - Environmental testing; 33.050.01 - Telecommunication terminal equipment in general. The ICS classification helps identify the subject area and facilitates finding related standards.

SIST EN 302 099 V1.1.1:2006 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

Standards Content (Sample)


SLOVENSKI STANDARD
01-februar-2006
Okoljski inženiring (EE) – Napajanje opreme v dostopovnem omrežju
Environmental Engineering (EE); Powering of equipment in access network
Ta slovenski standard je istoveten z: EN 302 099 Version 1.1.1
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
33.050.01 Telekomunikacijska Telecommunication terminal
terminalska oprema na equipment in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

European Standard (Telecommunications series)

Environmental Engineering (EE);
Powering of equipment in access network

2 ETSI EN 302 099 V1.1.1 (2002-01)

Reference
DEN/EE-02007
Keywords
access, network
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
Individual copies of the present document can be downloaded from:
http://www.etsi.org
The present document may be made available in more than one electronic version or in print. In any case of existing or
perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF).
In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive
within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
http://portal.etsi.org/tb/status/status.asp
If you find errors in the present document, send your comment to:
editor@etsi.fr
Copyright Notification
No part may be reproduced except as authorized by written permission.
The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2002.
All rights reserved.
ETSI
3 ETSI EN 302 099 V1.1.1 (2002-01)
Contents
Intellectual Property Rights.4
Foreword.4
1 Scope.5
2 References.5
3 Definitions and abbreviations.6
3.1 Definitions.6
3.2 Abbreviations.7
4 Powering configurations.7
4.1 Remote powering.8
4.1.1 Centralized powering.8
4.1.2 Cluster powering.9
4.2 Local powering.10
4.2.1 TE of access network, common to several customers.10
4.2.2 TE of access network, at customer's home .10
5 Effect of the technologies on the powering strategy .11
5.1 Powering strategy of family 1: metallic links.12
5.2 Powering strategy of family 2: non-metallic links .12
6 Requirements for local powering .13
6.1 TE including the power plant .13
6.2 TE powered by a dc voltage nominal -48 V local power unit .13
6.3 TE powered by a LPU with a dc voltage other than -48 V.13
6.4 TE powered by a nominal ac voltage nominal of 230 V, 50 Hz local power unit.13
7 Requirements for remote powering.13
7.1 Input of the Remote Power Unit.13
7.2 Output of the Remote Power Unit .13
7.3 Input characteristics of remote powered receiver in the voltage mode .14
7.4 Input characteristics of remote powered receiver in the current mode.14
8 Power back-up.14
9 Power management.14
10 Safety, EMC, protection.16
10.1 Product Safety.16
10.2 EMC.16
10.3 Protection/resistibility.16
10.4 Bonding and earthing .16
11 Environmental conditions.17
Annex A (normative): Battery sizing.18
A.1 Back-up power for telephone service.18
A.2 Autonomy of the back-up.18
A.3 Use of valve regulated lead acid battery.19
A.4 End of service life of battery .19
Annex B (informative): Bibliography.20
History .21

ETSI
4 ETSI EN 302 099 V1.1.1 (2002-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Environmental
Engineering (EE).
National transposition dates
Date of adoption of this EN: 25 January 2002
Date of latest announcement of this EN (doa): 30 April 2002
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 October 2002
Date of withdrawal of any conflicting National Standard (dow): 31 October 2002

ETSI
5 ETSI EN 302 099 V1.1.1 (2002-01)
1 Scope
The present document describes the principles for powering of telecommunications equipment in access network and
contains requirements for the powering systems, laying down:
- the characteristics of the input and output interfaces of the power units;
- the power back-up conditions for TE including a power unit;
- the management data, necessary to guarantee the availability of the service and to ensure the maintenance of the
power units.
The present document takes into account the characteristics of access network equipment for which the limits of
responsibility in the installation or design of the power plants are very different than for equipment of telecom centre: it
goes from "complete integration of the power plant in the TE" till "remote power feeding from a distant power plant".
The present document applies for the powering of all equipment of the access network (copper, fiber or radio networks)
located outside telecommunications centres. The access network is defined as the part of the telecommunications
network, which is comprised between the customer terminal installation and the first exchange (switching unit). The
customer terminal and the switching unit are excluded of the application field of the present document.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
[1] ETSI ETS 300 132-1: "Equipment Engineering (EE); Power supply interface at the input to
telecommunications equipment; Part 1: Operated by alternating current (ac) derived from direct
current (dc) sources".
[2] ETSI EN 300 132-2: "Environmental Engineering (EE); Power supply interface at the input to
telecommunications equipment; Part 2: Operated by direct current (dc)".
[3] Void.
[4] CENELEC EN 60950-1: "Information technology equipment - Safety - Part 1: General
requirements".
[5] IEC 60950-21: "Safety of information technology equipment - Part 21: Remote power feeding".
[6] CENELEC HD 472 S1 (1989): "Nominal voltages for low-voltage public electricity supply
systems".
[7] CENELEC HD 625.1: "Insulation coordination for equipment within low-voltage systems -
Part 1: Principles requirements and tests".
[8] CENELEC EN 50310: "Application of equipotential bonding and earthing in buildings with
information technology equipment".
[9] CENELEC EN 60896-2: "Stationary lead-acid batteries - General requirements and method of
test - Part 2: Valve regulated types".
[10] ETSI EN 300 019-1-1: "Environmental Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment; Part 1-1: Classification of environmental
conditions; Storage".
ETSI
6 ETSI EN 302 099 V1.1.1 (2002-01)
[11] ETSI EN 300 019-1-3: "Environmental Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment; Part 1-3: Classification of environmental
conditions; Stationary use at weatherprotected locations".
[12] ETSI ETS 300 019-1-4: "Equipment Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment; Part 1-4: Classification of environmental
conditions; Stationary use at non-weatherprotected locations".
[13] ETSI EN 300 019-1-8: "Environmental Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment; Part 1-8: Classification of environmental
conditions; Stationary use at underground locations".
[14] ETSI EN 300 253: "Environmental Engineering (EE); Earthing and bonding configuration inside
telecommunications centres".
[15] ITU-T Recommendation K.35: "Bonding configurations and earthing at remote electronic sites".
[16] ETSI EG 201 212: "Electrical safety; Classification of interfaces for equipment to be connected to
telecommunication networks".
[17] ITU-T Recommendation K.45: "Resistibility of access network equipment to overvoltages and
overcurrents".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document the following terms and definitions apply:
access network: part of a telecommunications network between the customer terminal installation and the first
switching unit
local powering: powering principle of a telecommunications equipment by a (dedicated) power unit implemented in the
same location
remote powering: power feeding of a telecommunications equipment by a remote power circuit
NOTE: Such a circuit consists of a remote power unit, distribution wiring, and fed receivers.
Remote Feeding Telecommunication (RFT) circuit: secondary circuit within the equipment, intended to supply or
receive dc power via a telecommunication network at voltages equal to or exceeding the limits for TNV circuits, and on
which overvoltages from telecommunication networks are possible
RFT-C circuit: RFT circuit which is so designed and protected that under normal operating conditions and single fault
conditions the currents in the circuit do not exceed defined values
RFT-V circuit: RFT circuit which is so designed and protected that under normal operating conditions and single fault
conditions the voltages are limited and the accessible area of contact is limited
centralized powering: remote powering in which the remote feeding source is located in a telecommunications centre
cluster powering: remote powering of a cluster of equipment (1 to n items of equipment), in which the remote feeding
source is located outside a telecommunications centre
Remote Power Unit (RPU): power unit, connected to the mains or from a centralized power plant, which supplies
distant telecommunications equipment
distant power receiver: power equipment electrically connected to a Remote Power Unit
NOTE: Its function is to supply telecommunications equipment situated at the same location. It may be combined
with the item of telecommunications equipment itself.
ETSI
7 ETSI EN 302 099 V1.1.1 (2002-01)
Local Power Unit (LPU): power supply equipment whose function is to supply a telecommunication equipment
situated at the same location
NOTE: It is generally locally connected to the mains and provides dc or ac voltage output to feed
telecommunication equipment.
SELV circuit: See EN 60950-1 [4].
TNV circuit: See EN 60950-1 [4].
hazardous voltage: See EN 60950-1 [4].
primary circuit: See EN 60950-1 [4].
secondary circuit: See EN 60950-1 [4].
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ac alternating current
CH Customer's Home
dc direct current
FTTB Fibre To The Building
FTTC Fibre To The Curb
FTTCab Fibre To The Cabinet
FTTH Fibre To The Home
LPU Local Power Unit
ONU Optical Network Unit
RFT Remote Feeding Telecommunication
RPU Remote Power Unit
TC Telecommunication's Centre
TE Telecom Equipment
TNV Telecommunication Network Voltage
UPS Uninterruptible Power Supply
4 Powering configurations
The main characteristic feature of the different powering architectures of access network equipment is the location of
the following two functions:
- the point of connection to the mains; and
- the place of power back-up.
The total network can be divided in three main parts:
1) the Telecommunication Centre (TC);
2) the field (the undefined area between the Telecom Centre and the Customer's Home);
3) the Customer's Home (CH).
Powering architectures
Equipment of access network can be powered remotely from a telecommunications centre (centralized powering) or
from a power supply node (cluster powering), or locally from the mains (local powering). Inside these three main
powering architectures, several configurations of powering are used. They are summarized in the clauses 4.1 to 4.2 and
in the figures 1, 2 and 3 by the acronyms PW1 to PW 9 (for powering).
ETSI
8 ETSI EN 302 099 V1.1.1 (2002-01)
Power back-up
For the telephone service, which needs to provide an available service even in the case of a mains outage, a power
back-up unit is located either in the remote power source or in the equipment powered. The clauses 4.1 to 4.2 detail the
different installation configurations.
Location of the Telecom Equipment (TE)
On the figures 1, 2 and 3 of the following clauses, the TE in access network is schematically represented in the field.
These figures mean that the TE can be implemented in different types of locations:
- in a customer's office;
- in a building, public or private;
- in an indoor cabinet;
- in a street cabinet;
- on a pole cabinet;
- in a telecommunications manhole, etc.
The TE provides services for several customers or for one professional customer.
On figure 3, the TE can be located at customer's home and provides services for only one private customer.
Power interfaces
Six power-feeding interfaces are mentioned in the following clauses: They are as follows:
I = Power interface between a -48 V power plant and the fed equipment in a telecom centre. It fits with the
interface "A" according to EN 300 132-2 [2].
I = Power interface between the public mains (commercial ac) and the fed equipment. It fits with the voltage
defined in HD 472 [6].
I = Power interface at the output of a remote power source.
I = Power interface at the input of a distant power receiver interface, in remote powering.
I = Power interface between a local power unit and the fed equipment, in local powering. It fits with the interface
"A" according to EN 300 132-2 [2] or with the interface defined in clauses 6.2 to 6.4.
I = Power interface between the public mains (commercial ac) or emergency power (UPS, diesel generator) or
interface "A" according to ETS 300 132-1 [1] and the fed equipment in a telecom centre. It fits with the
voltage defined in HD 472 [6].
4.1 Remote powering
4.1.1 Centralized powering
The different power supply configurations are detailed in figure 1. The output of the power source is defined at interface
I . It comes from a TE (PW1a) or from a specific remote power unit (RPU in PW1b). Interface I corresponds to the
2 0
input of the RPU. The remote power unit consists of protection and distribution devices and, possibly, power
conversion equipment. Interface I corresponds to Interface I and is located in the telecommunication centre.
5 1
In some cases, the TE of the access network may be equipped with a battery providing additional power in periods of
heavy traffic (PW3). This battery is recharged by the remote power supply during periods of light traffic.
ETSI
9 ETSI EN 302 099 V1.1.1 (2002-01)
Customer
terminal
TE
TE
PW1a
Remote
TE PW1b
Power
Unit
Central
TE TE PW2a
Power
Supply
Remote
TE
PW2b
Power
Unit
2 3
TE
PW3
Ad
Customer's
Access network equipment
Telecommunications centre
home
Additional power source (for traffic)
Ad
Figure 1: Centralized powering
4.1.2 Cluster powering
The different possible power supply configurations are detailed in figure 2. The remote power source, called Remote
Power Unit (RPU), serves a group of distant telecommunications equipment, from 1 to n. The RPU is installed in a
location (building, outdoor cabinet, manhole, etc.) which is distinct from the TE's building, cabinet or manhole. The
telephone service is backed up by batteries located either at the remote power unit (remote powering with back-up at
source, PW4) or in the telecommunications equipment (remote powering with local back-up, PW5).
Customer
terminal
TE
Remote
PW4
Power
Unit
Telecom-
munications
centre
TE
PW5
Remote
Power
Unit
Customer's
Access network equipment
home
Figure 2: Cluster powering
ETSI
...