ETSI TS 101 548-1 V2.2.1 (2018-06)

TECHNICAL SPECIFICATION
Access, Terminals, Transmission and Multiplexing (ATTM);
European Requirements for Reverse Powering
of Remote Access Equipment;
Part 1: Twisted pair networks
2 ETSI TS 101 548-1 V2.2.1 (2018-06)

Reference
RTS/ATTM-0632
Keywords
ADSL2plus, VDSL2
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3 ETSI TS 101 548-1 V2.2.1 (2018-06)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions, symbols and abbreviations . 8
3.1 Definitions . 8
3.2 Symbols . 9
3.3 Abbreviations . 9
4 Introduction to Reverse Power Feed . 11
5 Reverse Power Feed Architecture . 12
5.1 Basics of RPF . 12
5.2 Reverse Power Feed and POTS Co-Existence . 13
5.2.1 Overview . 13
5.2.2 POTS Adapters . 13
5.2.2.1 General . 13
5.2.2.2 POTS Adapter - E (POTSA-E) . 13
5.2.2.3 POTS Adapter - C (POTSA-C) . 13
5.2.2.4 POTS Adapter - D (POTSA-D) . 14
5.3 Reverse Power Feed Architecture without POTS on the same pair (RPFA-NOP). 14
5.4 Reverse Power Feed Architecture with Baseband POTS from the Exchange (RPFA-EXP). 15
5.5 Reverse Power Feed Architecture with Baseband POTS from the Exchange Sharing the in-premises
Wiring (RPFA-EXPSW) . 17
5.6 Reverse Power Feed Architecture with Derived POTS (RPFA-DRP) . 18
5.7 Reverse Power Feed Architecture with Derived POTS Sharing the in-premises Wiring (RPFA-DRPSW) . 19
5.8 Reverse Power Feed Architecture without POTS and with Broadband Bypass (RPFA-NOPBB) . 20
6 Reverse Power Feed Start-Up Protocol . 21
6.1 Introduction . 21
6.1.1 General . 21
6.1.2 Start-up in presence of MELT signature . 23
6.2 Metallic Detection based Start-Up (MDSU) Protocol . 24
6.2.1 Signature detection . 24
6.2.2 DPU classification using MDSU protocol . 27
6.2.3 Start-up Sequence diagram . 29
6.2.4 Start-up flow chart . 29
6.2.5 POTS RCR Protocol (PRP) - Optional extension of MDSU . 31
6.2.5.1 PRP definition . 31
6.2.5.2 PRP electrical specifications . 36
6.2.5.2.1 PSE electrical specification for PRP. 36
6.2.5.2.2 DPU electrical specification for PRP . 37
6.2.5.3 Interoperability between "PRP capable" and "non PRP capable devices" . 38
6.3 RPF Dying Gasp and Indication Primitives . 39
6.3.1 General . 39
6.3.2 DGL pulse sequence . 40
6.3.3 OHP pulse sequence . 40
6.3.4 BAT, BBA and ACM pulse sequences . 41
6.4 RPF Operations and Maintenance . 43
7 Reverse Power Feed Characteristics . 44
7.1 Safety Aspects . 44
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4 ETSI TS 101 548-1 V2.2.1 (2018-06)
7.1.1 Background . 44
7.1.2 Unintended consequences . 44
7.2 RPF Range Options and Classes . 44
7.3 Electrical reference model . 46
7.4 Zero touch DPU . 48
7.5 PSE and DPU PE electrical specification . 51
7.5.1 PSE electrical specification. 51
7.5.1.1 PSE electrical specification on interface U-R2P . 51
7.5.1.2 PSE isolation requirements . 53
7.5.2 DPU electrical specification . 53
7.5.2.1 Reach Resistance definition . 53
7.5.2.2 DPU electrical specification at U-O interface . 54
7.5.3 DPU power modes . 55
7.6 Micro-interruption requirements . 56
7.6.1 PSE micro-interruption requirements . 56
7.6.2 DPU micro-interruption specification . 56
8 Power Splitter Characteristics . 56
8.1 General . 56
8.2 Power Splitter class definition . 57
8.3 Description of Power Splitter Use Cases . 58
8.3.1 General . 58
8.3.2 DPU - case 1: No POTS service sharing the loop wiring . 58
8.3.3 DPU - case 2: With POTS service from the exchange . 59
8.3.4 DPU - case 3: With a Derived POTS service sharing the wiring . 60
8.3.5 CPE - case 1: No POTS service sharing the loop wiring . 61
8.3.6 CPE - case 2: With POTS service from the exchange . 61
8.3.7 CPE - case 3: With a derived POTS service sharing the wiring . 62
8.4 Power Splitter Requirements . 63
8.4.1 General . 63
8.4.2 DSL Insertion Loss . 63
8.4.3 DSL Impedance Conversion . 64
8.4.4 DSL-Band Noise Attenuation . 65
8.4.5 DSL Port DC Isolation Resistance . 65
8.4.6 POTS Measurement Procedure . 65
8.4.7 POTS Insertion Loss . 66
8.4.8 POTS Impedance Conversion . 67
8.4.9 POTS-band longitudinal Balance . 68
8.4.10 POTS-band Noise Attenuation . 69
8.4.11 POTS DC Isolation Resistance . 69
8.4.12 Tolerance to DC Feed . 69
8.4.13 Tolerance to Ringing . 70
8.4.14 Power Drain . 71
9 POTS Adapter Characteristics . 72
9.1 Introduction . 72
9.2 Description of POTS Adapters Use Cases . 73
9.2.1 General . 73
9.2.2 DPU - case 1: No POTS service sharing the loop wiring . 73
9.2.3 DPU - case 2: With a POTS service from the exchange - Adapter-E . 73
9.2.4 DPU - case 3: With a derived POTS service sharing the wiring . 74
9.2.5 CPE - case 1: No POTS service sharing the loop wiring . 74
9.2.6 CPE - case 2: With a POTS service from the exchange - Adapter-C . 74
9.2.7 CPE - case 2: With a POTS service from the exchange - Adapter-D . 74
9.2.8 CPE - case 3: With derived POTS sharing the wiring - Adapter-D . 75
9.2.9 CPE - case 3: With derived POTS sharing the wiring - Adapter-E . 76
9.3 POTS Adapter Requirements . 76
9.3.1 General . 76
9.3.2 DSL Insertion Loss . 76
9.3.3 DSL Impedance Conversion . 77
9.3.4 DSL-band Noise Generation . 77
9.3.5 POTS Measurement Procedure . 77
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5 ETSI TS 101 548-1 V2.2.1 (2018-06)
9.3.6 POTS Insertion Loss . 79
9.3.7 POTS Impedance Conversion . 80
9.3.8 POTS-band longitudinal Balance . 81
9.3.9 Signalling Channel Noise . 82
9.3.10 POTS DC Isolation Resistance . 82
9.3.11 Ringing Detection . 83
9.3.12 Ringing Generation . 84
9.3.13 DC Feed Detection. 84
9.3.14 DC Feed Generation . 85
9.3.15 Hook Switch . 85
9.3.16 Hook State Detection . 85
9.3.17 Bypass Mode . 86
9.3.18 Power Drain . 86
9.4 Out of Band Signalling Channel . 87
Annex A (informative): Reverse power backup systems . 88
A.1 Casef 1 battery backup in the CPE . 88
A.2 Case 2 battery backup in the DPU and CPE . 88
Annex B (normative): General POTS requirements . 89
Annex C (informative): RPF Noise Limits For Common Mode. 90
C.1 Introduction . 90
C.2 Derivation . 90
C.3 Cable Balance Model and Common Mode PSD Construction. 90
C.4 Measurement Environment . 90
Annex D (informative): Out-of-Band Signalling Channel . 92
Annex E (normative): PRP PSE low level flow charts . 94
E.1 General . 94
E.2 Perform MDSU . 95
E.3 POTS RCR MDSU Error Handler . 96
E.4 PSE Reverse Power Active . 97
E.5 Perform POTS RCR . 98
E.6 Send PRP Trigger . 99
E.7 Set Initial State . 100
E.8 Send Enable Trigger to POTS Adapter . 101
Annex F (informative): Long Range RPF Classification . 102
Annex G (informative): Bibliography . 103
Annex H (informative): Change History . 104
History . 105

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6 ETSI TS 101 548-1 V2.2.1 (2018-06)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://ipr.etsi.org/).
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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Access, Terminals, Transmission
and Multiplexing (ATTM).
The present document is part 1 of a multi-part deliverable covering the European requirements for reverse powering of
remote access equipment, as identified below:
Part 1: "Twisted pair networks";
Part 2: "Coaxial cable networks".
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 xDSL DSLAM equipment, 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 the distribution-side
copper network. The present document defines a reverse power feed transmission standard which allows Operators to
source suitably compliant equipment for inclusion in their networks. The reverse power feed methodology can be used
to power a remote node hosting any metallic transmission system (e.g. G.fast [i.4], VDSL2 [i.3], etc.).
ETSI
7 ETSI TS 101 548-1 V2.2.1 (2018-06)
1 Scope
The present document defines architectures and specifications for reverse powering of remote network nodes from one
or multiple CPEs over twisted pair networks. The architectures describe how to combine reverse power feed with the
data only, VoIP and POTS line services. Start-up protocols are defined to ensure proper interaction between the line
services and the reverse power system. Operations and maintenance requirements for managing the reverse power feed
and power combining within the remote network node are specified. The present document also identifies power splitter
and POTS Adapter requirements.
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 ES 202 971: "Access and Terminals (AT); Public Switched Telephone Network (PSTN);
Harmonized specification of physical and electrical characteristics of a 2-wire analogue interface
for short line interface".
[2] CENELEC EN 60950-1: "Information Technology Equipment - Safety, Part 1: General
requirements (IEC 60950-1:2005 + Cor.:2006 + A1:2009, modified)".
[3] ETSI ES 203 021: "Access and Terminals (AT); Harmonized basic attachment requirements for
Terminals for connection to analogue interfaces of the Telephone Networks; Update of the
technical contents of TBR 021, EN 301 437, TBR 015, TBR 017".
[4] Broadband Forum TR-301: "Architecture and Requirements for Fiber to the Distribution Point",
Issue 1.
[5] Broadband Forum TR-286: "Testing of Metallic Line Testing (MELT) functionality on xDSL
Ports".
[6] IEC 61000-4-11: "Electromagnetic compatibility (EMC) - Part 4-11: Testing and measuring
techniques - Voltage dips, short interruptions and voltage variations immunity tests".
[7] ETSI TS 101 952-1: "Access network xDSL splitters for European deployment; Part 1: Generic
specification of xDSL over POTS splitters".
[8] ETSI ES 203 021-3: "Access and Terminals (AT); Harmonized basic attachment requirements for
Terminals for connection to analogue interfaces of the Telephone Networks; Update of the
technical contents of TBR 021, EN 301 437, TBR 015, TBR 017; Part 3: Basic Interworking with
the Public Telephone Networks".
[9] CENELEC EN 62368-1: "Audio/video, information and communication technology equipment -
Part 1: Safety requirements".
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8 ETSI TS 101 548-1 V2.2.1 (2018-06)
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] Void.
[i.2] NICC ND 1645 (V1.1.2) (2011-06): "NGA Telephony; Architecture and requirements".
NOTE: Available at http://www.niccstandards.org.uk/files/current/ND1645v1.1.2.pdf?type=pdf.
[i.3] Recommendation ITU-T G.993.2: "Very high speed digital subscriber line transceivers 2
(VDSL2)".
[i.4] Recommendation ITU-T G.9700: "Fast access to subscriber terminals (G.fast) - Power spectral
density specification".
[i.5] Recommendation ITU-T G.9701: "Fast access to subscriber terminals (G.fast) - Physical layer
specification".
[i.6] ETSI TS 101 271 (V1.2.1): "Access, Terminals, Transmission and Multiplexing (ATTM);Access
transmission systems on metallic access cables; Very High Speed digital subscriber line system
(VDSL2) [Recommendation ITU-T G.993.2 modified]".
[i.7] Recommendation ITU-T G.998.4, Annex E: "Low Power Mode operation with ITU-T G.993.2 and
G.993.5".
[i.8] Recommendation ITU-T G.9701, Amendment 1 (2014): "Support of Low power operation and all
functionality necessary to allow transceivers to be deployed as part of reverse powered (and
possibly battery operated) network equipment".
[i.9] Recommendation ITU-T G.992.5: "Asymmetric digital subscriber line 2 transceivers (ADSL2)
Extended bandwidth ADSL2 (ADSL2plus)".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Broadband bypass: scenario whereby the DPU supports "Reverse Power Feed Architecture - No POTS with
Broadband Bypass" (RPFA NOP-BB) as defined in clause 5.8
NOTE: The scenario whereby the DPU supports ZT-RCR defined in clause 7.4 whereby exchange POTS is not
present on the line, but where there is an overlay DSL service (i.e. "naked" or "dry" DSL).
bypass mode: operational state of the POTS adapters or power splitter where there is a metallic connection to the
exchange or to an ATA
NOTE: This also refers to the the operational state of the stateless Switching Function (SF) specifically for the
RPFA-NOPBB architecture option, where the xTU-R of the CPE is connected to the xTU-O of the
CO/cabinet.
metallic connection: physical connectivity providing a DC path between two points, typically provided via a pair of
twisted copper (or aluminium) wires
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9 ETSI TS 101 548-1 V2.2.1 (2018-06)
normal mode: operational state of the POTS adapters or power splitter where there is no metallic connection to the
exchange or to an ATA
NOTE: This also refers to the operational state of the stateless Switching Function (SF), specifically for the
RPFA-NOPBB architecture option, where the xTU-R of the CPE is connected to the xTU-O of the DPU.
normal operation: state of a system (i.e. a DPU reversely powered by a PSE) reached after the start-up procedure has
been completed
POTS adapter: device that provides DC isolation between reverse power feed and POTS DC feed to allow a POTS
service to share the same wires as those used by reverse power feed
POTS DC feed: DC current presented at a POTS adapter to power a plain old telephone
POTS Remote Copper Reconfiguration (RCR): scenario where POTS from the exchange may be provided to the
subscriber and shall be disconnected by the DPU, prior to start-up of the DPU
power splitter: device that performs a frequency splitting/combining function between the AC part of the services
being carried (which can include POTS and xDSL based services) and the injected DC electrical power
NOTE: The power splitter does not include a DC-blocking high-pass function.
RING: other leg of a twisted pair
service splitter: low pass filter that separates baseband POTS from xDSL frequencies
NOTE: The relevant specifications for the service splitter can be found in ETSI TS 101 952-1 [7].
start-up mode: start-up procedure of a system (powering part of a DPU and PSE)
TIP: one leg of a twisted pair
3.2 Symbols
For the purposes of the present document, the following symbols apply:
Ω Ohm
μF micro Farad
nF nano Farad
R 2-wire analogue presented interface
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-R2S Reference point at CPE containing the baseband POTS and the converted POTS signalling
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-O2O Reference point at DPU containing the baseband POTS and the converted POTS signalling
U-O2P Reference point at DPU containing the extracted DC power
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
ACM Alternating Current Mains
ADSL Asymmetric Digital Subscriber Line
ATA Analogue Telephone Adapter
BAT Battery
BBA Battery Back-up Available
CO Central Office
CP Customer Premises
CPE Customer Premises Equipment
CPE ME CPE's Management Entity
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10 ETSI TS 101 548-1 V2.2.1 (2018-06)
CPF Common Power Feed
DC Direct Current
DGL Dying Gasp Loss
DN Distribution Network
DP Distribution Point
DPU Distribution Point Unit
DPU ME DPU's Management Entity
DR Diode/Resistor
DSL Digital Subscriber Line
DSLAM Digital Subscriber Line Access Multiplexer
ELC Error Line Condition
EXPSW Exchange Sharing the in-premises Wiring
FSK Frequency Shift Keying
FTTdp Fibre To The distribution point
FTU G.fast Transceiver Unit
NOTE: See Recommendation ITU-T G.9701 [i.5].
FTU-O FTU at the DPU
FTU-R FTU at the remote site
HON Higher Order Node
IFN Intensity of current Feed Now
LPF Low Pass Filter
LR Long Range
LSU Last Start Up
MDSU Metallic Detection based Start-Up protocol
ME Management Entity
MELT Metallic Loop Test
NMS Network Management System
NT Network Termination
NTE Network Termination Equipment
OAM Operations And Maintenance
OHP Off-Hook Phone
PC Power Class
PE Power Extractor
PHY Physical (layer)
PMA Persistent Management Agent
PME-C CPE's Power Management Entity
PME-D DPU's Power Management Entity
PMT Power Management Transceiver
POTS Plain Old Telephony Service
PRP POTS Remote Copper Reconfiguration (RCR) Protocol
PS Power Splitter
PSD Power Spectral Density
PSE Power Source Equipment
PSU Power Supply Unit (including the combiner function if multiple lines are active)
PT PRP Trigger
PTID PRP Trigger IDentification
RBW Resolution Bandwidth
RC Resistor/Capacitor
RCR Remote Copper Reconfiguration
RPCE Reverse Power Control Entity
RPF Reverse Power Feed
RPFA Reverse Power Feed Architecture
RPFA-DRP Reverse Power Feed Architecture - Derived POTS
RPFA-DRPSW Reverse Power Feed Architecture - Derived POTS Sharing in-premises Wiring
RPFA-EXP Reverse Power Feed Architecture - Exchange POTS
RPFA-EXPSW Reverse Power Feed Architecture - Exchange POTS Sharing in-premises Wiring
RPFA-NOP Reverse Power Feed Architecture - No POTS
RPFA-NOPBB Reverse Power Feed Architecture - No POTS with Broadband Bypass
R Signature Resistor
SIG
SCF Switch Control Function
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11 ETSI TS 101 548-1 V2.2.1 (2018-06)
SF Switching Function
SG Service Gateway
SIG Signature
SR Short Range
SS Service Splitter
TNV Telecommunication Network Voltage
UPS Uninterrupted Power Supply
VA Volt Ampere
VDSL Very high speed Digital Subscriber Line
VoIP Voice over Internet Protocol
VPSE Steady state voltage from PSE
xDSL unspecified DSL variant
xTU-O FTU-O or VTU-O
xTU-R FTU-R or VTU-R
ZRC Zener/Resistor/Capacitor
ZT-RCR Zero Touch Remote Copper Reconfiguration
ZT-LAC Zero Touch Link Auto Configuration
4 Introduction to Reverse Power Feed
The basic architecture of a fibre-fed remote node with reverse power feed is shown in Figure 1.

Figure 1: Generic Fibre-fed Remote Node Architecture with reverse power feed
Figure 1 shows power being injected at the NTE from a local power source (located within the home and/or building)
which traverses the local loop to power a fibre-fed remote node which can be located at either the distribution
point (DP) or street cabinet using the same copper pair cable that is used to transmit the xDSL to/from the
home/fibre-fed remote node. A metallic POTS service is shown at the NTE. Voice services can also be implemented as
a derived service from the service gateway (SG).
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.
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12 ETSI TS 101 548-1 V2.2.1 (2018-06)
There may be occasions where only a single user is providing power to the remote node but this may not be sufficient to
power all of the remote node electronics for proper operation.
It is recognized that one single (i.e. generic) specification cannot consider all possible architectural variants, therefore
the present document has been organized as a series of architecture options and equipment shall adhere to one or more
of these options.
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 Architecture
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 copper lines 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 services being carried (which can include POTS and
xDSL based services) 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 six
options shown in Table 1. The optional reverse power battery backup at the customer premises is illustrated in block
BAT for each reference model.
Table 1: Architecture Options for Reverse Power Feed
Option Name Description
1 RPFA-NOP Reverse Power Feed Architecture - No POTS
2 RPFA-EXP Reverse Power Feed Architecture - Exchange POTS
3 RPFA-EXPSW Reverse Power Feed Architecture - Exchange POTS Sharing in-premises Wiring
4 RPFA-DRP Reverse Power Feed Architecture - Derived POTS
5 RPFA-DRPSW Reverse Power Feed Architecture - Derived POTS Sharing in-premises Wiring
6 RPFA-NOPBB Reverse Power Feed Architecture - No POTS with Broadband Bypass

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13 ETSI TS 101 548-1 V2.2.1 (2018-06)
5.2 Reverse Power Feed and POTS Co-Existence
5.2.1 Overview
Table 1, option 2 to option 5 involve reverse power feed co-existing with POTS - whether this is exchange based POTS
(RPFA-EXP, RPFA-EXPSW) or derived POTS (RPFA-DRP, RPFA-DRPSW).
When a POTS service is present on the same wire pair as reverse power feed (option 2, option 3 and option 5) the POTS
DC feed will be removed and the DC signalling/low frequency signalling will be translated so that it uses another part
of the baseb
...