ETSI TS 101 548-2 V1.1.1 (2021-06)

Access, Terminals, Transmission and Multiplexing (ATTM); European Requirements for Reverse Powering of Remote Access Equipment; Part 2: Coaxial Cable Networks

DTS/ATTM-0633

General Information

• Status: Not Published
• Technical Committee: ATTM TM6 - Wireline Access Network Systems
• Current Stage: 12 - Completion
• Due Date: 15-Jul-2021
• Completion Date: 21-Jun-2021

Standards Content (Sample)

ETSI TS 101 548-2 V1.1.1 (2021-06)






TECHNICAL SPECIFICATION
Access, Terminals, Transmission and Multiplexing (ATTM);
European Requirements for Reverse Powering
of Remote Access Equipment;
Part 2: Coaxial Cable Networks

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2 ETSI TS 101 548-2 V1.1.1 (2021-06)

Reference
DTS/ATTM-0633
Keywords
cables, coaxial, powering, reverse, RPF

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ETSI

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3 ETSI TS 101 548-2 V1.1.1 (2021-06)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definition of terms, symbols and abbreviations . 7
3.1 Terms . 7
3.2 Symbols . 7
3.3 Abbreviations . 7
4 Introduction to Reverse Power Feed . 9
5 Reverse Power Feed Architectures . 10
5.1 Basics of RPF . 10
5.2 Reverse Power Feed Coax Architecture - G.fast Only (RPFA-CGO) . 11
5.3 Reverse Power Feed Coax Architecture with G.fast and Satellite TV (RPFA-CGS) . 13
6 Reverse Power Feed Start-Up Protocol . 14
6.1 Introduction . 14
6.1.1 General . 14
6.2 Metallic Detection based Start-Up (MDSU) Protocol . 15
6.3 RPF Dying Gasp and Indication Primitives . 16
6.4 RPF Operations and Maintenance . 16
7 Reverse Power Feed Characteristics . 16
7.1 Safety Aspects . 16
7.1.1 Background . 16
7.2 RPF Range options and Classes . 17
7.3 PSE and DPU PE electrical specification . 18
7.3.1 PSE electrical specification. 18
7.3.1.1 PSE electrical specification on interface U-R2P . 18
7.3.1.2 Earthing Requirements at Customer Premises . 19
7.3.2 DPU electrical specification . 19
7.3.2.1 Reach Resistance definition . 19
7.3.2.2 DPU electrical specification at U-O interface . 20
7.3.3 Polarity requirements . 22
7.3.4 DPU earthing requirements. 22
7.3.4.0 DPU earthing alternatives . 22
7.3.4.1 OSCs bonded together and to earth . 22
7.3.4.2 OSCs bonded together and isolated from earth . 22
7.3.4.3 OSCs isolated from each other and isolated from earth . 22
7.4 Micro-interruption requirements . 22
7.4.1 PSE micro-interruption requirements . 22
7.4.2 DPU micro-interruption specification . 23
8 Power Splitter Characteristics . 23
8.1 General . 23
8.2 Power Splitter class definition . 24
8.3 Power Splitter Requirements . 24
8.3.1 General . 24
8.3.2 DSL Insertion Loss . 24
8.3.3 DSL Impedance Conversion . 24
8.3.4 DSL-Band Noise Attenuation . 25
ETSI

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4 ETSI TS 101 548-2 V1.1.1 (2021-06)
8.3.5 DSL Port DC Isolation Resistance . 25
8.3.6 Passband Metallic Connection . 25
8.3.7 Pass band DC isolation . 25
9 RPF diplexer requirements . 26
9.1 General . 26
9.2 Reverse power feed to Satellite TV DC isolation resistance . 26
9.3 Reverse Power Feed Passband . 26
9.3.1 Passband Metallic Connection . 26
9.3.2 Pass band DC isolation . 27
Annex A (informative): Change History . 28
History . 29

ETSI

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5 ETSI TS 101 548-2 V1.1.1 (2021-06)
Intellectual Property Rights
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Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Access, Terminals, Transmission
and Multiplexing (ATTM).
The present document is part 2 of a multi-part deliverable. Full details of the entire series can be found in part 1 [1].
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
As various Operators consider the deployment of fibre-fed remote nodes that contain G.fast DSLAM equipment [i.1], it
is necessary to consider the means of powering such remotely located equipment. One such method, known as "reverse
power feed", transmits the power from the customer premises to the fibre-fed remote node using a point to point coaxial
cable network. The present document defines a reverse power feed transmission standard which allows Operators to
source suitably compliant equipment for inclusion in their networks.

ETSI

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6 ETSI TS 101 548-2 V1.1.1 (2021-06)
1 Scope
The present document defines architectures and specifications for reverse powering of a remote network node from one
or multiple G.fast CPEs over Point to Point (P2P) coaxial cable (coax), where there is no coexistence with other
services over an operational Hybrid Fibre Coax (HFC) network. The present document specifies the reverse powering
for two coax configurations with G.fast as described in Annex D.1 of BBF TR-285 [3], Issue 1 Amendment 1: G.fast
with satellite TV and G.fast only. The relevant clauses to ETSI TS 101 548-1 [1] are referenced where appropriate.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] ETSI TS 101 548-1: "Access, Terminals, Transmission and Multiplexing (ATTM); European
Requirements for Reverse Powering of Remote Access Equipment; Part 1: Twisted Pair
Networks".
[2] EN 62368-1: "Audio/video, information and communication technology equipment - Part 1: Safety
requirements", produced by CENELEC.
[3] Broadband Forum TR-285: "Broadband Copper Cable Models".
[4] Broadband Forum TR-301: "Architecture and Requirements for Fiber to the Distribution Point".
[5] EN 60728-11: "Cable networks for television signals, sound signals and interactive services -
Part 11: Safety" Edition 4.0 2016-3, produced by CENELEC.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Recommendation ITU-T G.9700: "Fast access to subscriber terminals (G.fast) - Power spectral
density specification".
[i.2] Recommendation ITU-T G.9701: "Fast access to subscriber terminals (G.fast) - Physical layer
specification".
ETSI

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7 ETSI TS 101 548-2 V1.1.1 (2021-06)
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
Core Conductor (CC): conductor at the center of a coax cable, normally a solid wire
diplexer: passive device that implements frequency-domain multiplexing, in which the two ports (in different
frequency bands) are multiplexed onto a third port Consequently, the input signals can coexist on the output port
without interfering with each other
metallic connection: physical connectivity providing a DC path between two points, typically provided via a coaxial
cable
normal operation: state of a system (i.e. a DPU reversely powered by a PSE) reached after the start-up procedure has
been completed
Outer Shield Conductor (OSC): conductor surrounding the core conductor insulation, normally a braided conductive
material
power splitter: device that performs a frequency splitting/combining function between the AC part of the services
being carried (which can include G.fast based services) and the injected DC electrical power
RG-x: Radio Guide - Standard Coaxial Cable designations
start-up mode: start-up procedure of a system (powering part of a DPU and PSE)
3.2 Symbols
For the purposes of the present document, the following symbols apply:
Ω Ohm
μF micro Farad
nF nano Farad
U-R Reference point at CPE containing both DC power and service data
U-R2 Reference point at CPE containing the filtered service data
U-R2P Reference point at CPE containing the injected DC power
U-O Reference point at DPU containing both DC power and service data
U-O2 Reference point at DPU containing the filtered service data
U-O2P Reference point at DPU containing the extracted DC power
U-OG Reference Point at DPU containing the G.fast signal
U-OS Diplexer Reference Point at the DP
U-RG Reference Point at CPE containing the G.fast signal
U-RS Diplexer Reference poin at CP
SAT TV Reference Point at DPU containing the satellite TV signal
STB TV Reference Point at CPE containing the satellite TV signal
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
ACM Alternating Current Mains
ATA Analogue Telephone Adapter
BAT Battery
BBA Battery Back-up Available
CC Core Conductor
CO Central Office
CP Customer Premises
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8 ETSI TS 101 548-2 V1.1.1 (2021-06)
CPE ME CPE's Management Entity
CPE Customer Premises Equipment
CPF Common Power Feed
DC Direct Current
DGL Dying Gasp Loss
DN Distribution Network
DP Distribution Point
DPU ME DPU's Management Entity
DPU Distribution Point Unit
DSL Digital Subscriber Line
DSLAM Digital Subscriber Line Access Multiplexer
ECL Error Line Condition
ELC Error Line Condition
FTU G.fast Transceiver Unit
NOTE: See Recommendation ITU-T G.9701 [i.2].
FTU-O FTU at the DPU
FTU-R FTU at the remote site
HON Higher Order Node
IFN Intensity of current Feed Now
MDSU Metallic Detection based Start-Up protocol
MDU Multi Dwelling Unit
ME Management Entity
MELT Metallic Loop Test
MET Main Earthing Terminal
NMS Network Management System
NT Network Termination
NTE Network Termination Equipment
OAM Operations And Maintenance
OSC Outer Shield Conductor
PC Power Class
PE Power Extractor
PHY Physical (layer)
PIS Potential Ignition Source
PME-C CPE's Power Management Entity
PME-D DPU's Power Management Entity
PMT Power Management Transceiver
PS Power Splitter
PSD Power Spectral Density
PSE Power Source Equipment
PSE-IE Power Source Equipment - Injected Energy
PSU Power Supply Unit (including the combiner function if multiple lines are active)
RBW Resolution Bandwidth
RG Radio Guide - Standard Coaxial Cable designations
RPF Reverse Power Feed
RPFA Reverse Power Feed Architecture
RPFA-CGO Reverse Power Feed Architecture - Coax G.fast Only
RPFA-CGS Reverse Power Feed Architecture - Coax G.fast with Satellite TV
R Signature Resistor
SIG
SAT Satellite
SG Service Gateway
SIG Signature
SR Short Range
STB Set Top Box
VA Volt Ampere
VPSE Steady state voltage from PSE
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9 ETSI TS 101 548-2 V1.1.1 (2021-06)
4 Introduction to Reverse Power Feed
The basic architecture of a fibre-fed remote node with reverse power feed over coax is shown in Figure 1.
Set Top Box
MDU Sat.
Local DC
Antenna
Power
Amplifier
Source
DPU diplexer diplexer
CO
Derived POTS
SG
NTE
Fibre-fed Remote
Central
Home network
Local Power
Power fed to remote node
Unit in DP
Office
Feed
over the same point-to-
point coax In MDU (1 user
only) as G.fast signal

Figure 1: Generic Fibre-fed Remote Node Coaxial Architecture with Reverse Power Feed
Figure 1 applies to two architecture scenarios, G.fast co-existing with Satellite TV and G.fast on its own. It shows
power being injected at the NTE from a local power source (located within the home and/or building) which traverses
the coaxial cable to power a fibre-fed remote node, located at the Distribution Point (DP).This is the same coaxial cable
that is used to transport the G.fast signal between the home and the fibre-fed remote node. Voice service can also be
implemented as derived POTS from the Service Gateway (SG). In the case of G.fast with satellite TV, a set of diplexers
is required to merge the satellite TV signals onto the same coax as used for the reverse power feed and G.fast signals.
Furthermore, reverse powering is not compatible with any use case where a DC component is used in the signalling
between the Set Top Box and the satellite TV distribution equipment.
An issue with regards to reverse powered fibre-fed nodes is that of who or what is responsible for the powering of
common circuitry contained within the node. It is easy to envisage that an individual user should be responsible for the
powering of the remote line terminating/driver electronics corresponding to his particular circuit. However, it is not so
easy to determine who or what is responsible for powering of say the DPU that terminates the fibre link.
The present document defines the following two deployment scenarios:
• Scenario 1 - DPU located G.fast only
• Scenario 2 - DPU located G.fast with satellite television
These two scenarios are shown below. These are derived from Figures 25 and 26 in TR-285 [3].
Point to Point coax (no other customers connected
to this coax) carrying G.fast and Reverse Power
from PSE to DPU
G.fast FTU-O
G.fast FTU-R and PSE at
At DPU
customer premises

Figure 2: Coax configuration for DPU located G.fast only
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10 ETSI TS 101 548-2 V1.1.1 (2021-06)
Point to Point coax (no other
customers connected to this
Coax carrying G.fast
Coax carrying G.fast
coax)carrying G.fast, Reverse
and Reverse Power
and Reverse Power
Power from PSE to DPU and AC
from PSE to DPU
from PSE to DPU
Satellite TV signals
Diplexer Diplexer
at DPU at customer premises
G.fast FTU-O
G.fast FTU-R and PSE at
G.fast G.fast
at DPU
customer premises
Common Common
RPF
Satellite TV distribution
Set-top box
Sat. Sat.
at customer premises
Sat. interface is AC coupled
Satellite TV
towards G.fast and Common
distribution
Remote Power
interfaces
equipment
Feeding source
(Antenna, LNB
Coax carrying AC Satellite TV
or switch, …)
signals and Remote Power
Satellite TV
feeding from local source for
Coax carrying AC
distribution to
Satellite Antenna amplifier,
Satellite TV signals
other residences
repeaters,.

Figure 3: Coax configuration for DPU located G.fast with Satellite TV
In the present document, two different implementations of Power Source Equipment (PSE) for Customer Premises are
considered: standalone (i.e. a two box model where the PSE and NTE are separate) or integrated (i.e. a single box
model where the PSE and NTE are integrated). In these implementations, the Power Splitter (PS) may either be
integrated or stand alone.
5 Reverse Power Feed Architectures
5.1 Basics of RPF
Reverse power feed is one of three DPU powering methods defined in TR-301 [4]. Here, the DPU draws its power from
the customer premises via the coaxial cable running between those premises and the DPU. The reverse power feed
capacity and DPU power consumption need to be such that the DPU can be fully operational when only a single
customer is connected. Any back-up battery would be located in the customer premises.
The other two methods are:
• Forward Power from a Network Power Node. In this case, any back-up battery would be located at the
network power node.
• Local Power from AC mains source. In this case, any back-up battery would be located at the DPU location.
The combination of reverse powering with one or both of the other two methods is outside the scope of the present
document.
Reverse powering shall have two power splitters (one located at the customer premises and another at the remote node)
to enable power to be inserted at the customer end of a link and extracted at the remote node. Each power splitter
performs a frequency splitting and combining function between the G.fast service being carried and the injected DC
electrical power.
Within the remote node, if it operates with multiple power-fed lines then there shall be a power extraction and combiner
unit. The purpose of this unit is to combine the multiple power feed inputs to produce a single power source output. The
power load should be shared amongst the input power sources.
The technical specifications in the present document shall apply to each architecture described below as one of the two
options shown in Table 1. The optional reverse power battery backup at the customer premises is illustrated in block
BAT for each reference models in Figure 4 and Figure 5.
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11 ETSI TS 101 548-2 V1.1.1 (2021-06)
Table 1: Architecture Options for Reverse Power Feed Over Coax
Option Name Description
1 RPFA-CGO Reverse Power Feed Architecture - Coax G.fast Only
2 RPFA-CGS Reverse Power Feed Architecture - Coax G.fast with Satellite TV

5.2 Reverse Power Feed Coax Architecture - G.fast Only
(RPFA-CGO)
The functional reference model of the reverse power feed coax architecture with G.fast only (RPFA-CGO) is shown in
Figure 4 (single derived POTS port) and Figure
...