ETSI ETS 300 012-5 ed.2 (1998-10)

Integrated Services Digital Network (ISDN); Basic User-Network Interface (UNI); Part 5: Conformance test specification for interface IB

RE/TM-03038-5

Digitalno omrežje z integriranimi storitvami (ISDN) – Osnovni vmesnik uporabnik-omrežje (UNI) – 5. del: Specifikacija za preskušanje skladnosti za vmesnik IB

General Information

• Status: Published
• Publication Date: 05-Oct-1998
• Technical Committee: TM 3 - Interfaces, architecture and functional requirements of transport netw
• Current Stage: 12 - Completion
• Due Date: 02-Oct-1998
• Completion Date: 06-Oct-1998
• Ref Project: SIST ETS 300 012-5 E2:2003 - Integrated Services Digital Network (ISDN); Basic User-Network Interface (UNI); Part 5: Conformance test specification for interface IB

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 012-5 E2:2003
01-december-2003
Digitalno omrežje z integriranimi storitvami (ISDN) – Osnovni vmesnik uporabnik-
omrežje (UNI) – 5. del: Specifikacija za preskušanje skladnosti za vmesnik IB
Integrated Services Digital Network (ISDN); Basic User-Network Interface (UNI); Part 5:
Conformance test specification for interface IB
Ta slovenski standard je istoveten z: ETS 300 012-5 Edition 2
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
SIST ETS 300 012-5 E2:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ETS 300 012-5 E2:2003

---------------------- Page: 2 ----------------------

SIST ETS 300 012-5 E2:2003
EUROPEAN ETS 300 012-5
TELECOMMUNICATION October 1998
STANDARD Second Edition
Source: TM Reference: RE/TM-03038-5
ICS: 33.020
Key words: Basic, ISDN, layer 1, testing, transmission, UNI
Integrated Services Digital Network (ISDN);
Basic User Network Interface (UNI);
Part 5: Conformance test specification for interface I
B
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Internet: [e-mail] - http://www.etsi.fr - http://www.etsi.org
Tel.: [phone] - Fax: [phone]
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 1998. All rights reserved.

---------------------- Page: 3 ----------------------

SIST ETS 300 012-5 E2:2003
Page 2
ETS 300 012-5: October 1998
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Standards Making Support Dept." at the address shown on the title page.

---------------------- Page: 4 ----------------------

SIST ETS 300 012-5 E2:2003
Page 3
ETS 300 012-5: October 1998
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions, symbols and abbreviations.8
3.1 Definitions .8
3.2 Symbols .9
3.3 Abbreviations .9
4 Allocation of tests .10
4.1 Scope.10
4.2 References .10
4.3 Definitions, symbols and abbreviations.10
4.4 Primitives associated with layer 1 .11
4.5 Wiring configurations and location of interface points .11
4.6 Functional characteristics .11
4.7 Interface procedures.12
4.8 Electrical characteristics .13
4.9 Power feeding.14
4.10 Interface connector contact assignment.15
4.11 Annexes.15
5 Functional characteristic tests.16
5.1 Binary organization of frame.16
5.1.1 Test A.16
5.1.2 Test B.17
6 Interface procedure tests .18
6.1 D-channel interframe (layer 2) time fill.18
6.2 D-echo channel response.18
6.3 Activation/deactivation .19
6.3.1 Activation/deactivation procedure .19
6.3.2 Activation/deactivation time.20
6.3.2.1 NT activation time.20
6.3.2.1.1 Test A in state G1 .21
6.3.2.1.2 Test B in state G2 .21
6.3.2.2 Deactivation time .22
6.3.2.3 Value of the timer T2 .22
6.4 Frame alignment procedures.23
7 Electrical characteristics tests .23
7.1 Bit rate.24
7.1.1 Bit rate when transmitting an INFO 2 .24
7.1.2 Bit rate when transmitting an INFO 4 .24
7.2 NT jitter characteristics .25
7.3 NT transmitter output impedance .25
7.3.1 Test A.25
7.3.2 Test B.26
7.4 Pulse shape and amplitude.27
7.5 Pulse unbalance .28
7.5.1 Pulse amplitude.28
7.5.2 Pulse unbalance of an isolated couple of pulses .28
7.6 Longitudinal conversion loss of transmitter output.29
7.7 Receiver input characteristics.29
7.7.1 NT receiver input impedance .29

---------------------- Page: 5 ----------------------

SIST ETS 300 012-5 E2:2003
Page 4
ETS 300 012-5: October 1998
7.7.1.1 Test A. 30
7.7.1.2 Test B. 30
7.7.2 Receiver sensitivity - noise and distortion immunity . 31
7.7.3 NT receiver input delay characteristics. 32
7.7.4 Unbalance about earth of the receiver input. 32
8 Power feeding. 33
8.1 Power source 1 . 33
8.1.1 Normal power condition. 33
8.1.2 Restricted power provision . 34
8.1.3 Power source switch-over time. 35
8.1.4 Power source 1 restricted mode under overload conditions. 36
8.1.4.1 Test A. 36
8.1.4.2 Test B. 36
8.1.4.3 Test C . 37
8.1.4.4 Test D . 38
8.1.5 Requirements for type "a" sources . 38
8.1.6 Switch on surge capability . 39
8.1.7 TE connection surge capability. 40
8.1.8 dc unbalance of power source 1. 41
8.1.9 Current unbalance in a pair . 43
8.2 Minimum voltage of power source 2 . 44
9 Auxiliary power supply . 44
9.1 Additional requirements from an APS. 44
9.1.1 APS switch-on time. 45
9.1.2 APS switch-off time. 46
9.1.3 APS requirements for type "a" sources . 47
9.1.4 APS switch-on surge capability. 48
9.1.5 APS TE connection surge capability. 49
9.1.6 APS current unbalance in a pair . 50
9.2 Additional requirements for NT compatible with APS . 50
9.2.1 Power source 1 mode back-off. 51
9.2.2 Power source 1 restricted mode power-up. 52
9.2.3 Power consumption from APS normal mode . 53
Annex A (normative): Connection cords and general testing requirements . 54
A.1 Connection cords. 54
A.2 General testing requirements . 54
History. 56

---------------------- Page: 6 ----------------------

SIST ETS 300 012-5 E2:2003
Page 5
ETS 300 012-5: October 1998
Foreword
This second edition European Telecommunication Standard (ETS) has been produced by the ETSI
Technical Committee Transmission and Multiplexing (TM).
This ETS concerns the basic User Network Interface (UNI) for the Integrated Services Digital Network
(ISDN) and consists of 7 parts as follows:
Part 1: "Layer 1 specification";
Part 2: "Implementation Conformance Statement (ICS) and Implementation eXtra Information for
Testing (IXIT) specification for interface I ";
A
Part 3: "Implementation Conformance Statement (ICS) and Implementation eXtra Information for
Testing (IXIT) specification for interface I ";
B
Part 4: "Conformance test specification for interface I ";
A
Part 5: "Conformance test specification for interface I ";
B
Part 6: "Abstract Test Suite (ATS) specification for interface I ";
A
Part 7: "Abstract Test Suite (ATS) specification for interface I ";
B
and is based on ITU-T Recommendation I.430 [1].
Transposition dates
Date of adoption of this ETS: 18 September 1998
Date of latest announcement of this ETS (doa): 31 January 1999
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 July 1999
Date of withdrawal of any conflicting National Standard (dow): 31 July 1999

---------------------- Page: 7 ----------------------

SIST ETS 300 012-5 E2:2003
Page 6
ETS 300 012-5: October 1998
Blank page

---------------------- Page: 8 ----------------------

SIST ETS 300 012-5 E2:2003
Page 7
ETS 300 012-5: October 1998
1 Scope
This part 5 of ETS 300 012 provides the test principles for the requirements of this ETS used to determine
the compliance of an Implementation Under Test (IUT) to this ETS.
It is outside the scope of this ETS to identify the specific tests required by an implementation where
equipment has to meet attachment approval.
Detailed test equipment accuracy and the specification tolerance of the test devices is not a subject of this
ETS. Where such details are provided then those test details are to be considered as being an
"informative" addition to the test description.
Unless otherwise stated, conformance tests described in this ETS do not apply to the Auxiliary Power
Supply (APS).
Ideal values for components and circuits are considered in the test principles.
2 Normative references
This ETS incorporates by dated and undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this ETS only when incorporated in it by amendment or revision. For undated references the latest
edition of the publication referred to applies.
[1] ITU-T Recommendation I.430 (1995): "Basic user-network interface; Layer 1
specification".
[2] ITU-T Recommendation I.411 (1993): "ISDN user-network interfaces; reference
configurations".
[3] ETS 300 047-3 (1992): "Integrated Services Digital Network (ISDN); Basic
access - safety and protection; Part 3: Interface I - protection".
A
[4] EN 60603-7 (1993): "Connectors for frequencies below 3 MHz for use with
printed boards - Part 7: Detail specification for connectors, 8-way, including fixed
and free connectors with common mating features; (IEC 603-7:1990) (S)".
[5] EN 28877 (1993): "Information technology; Telecommunications and information
exchange between systems; Interface connector and contact assignments for
ISDN Basic Access Interface located at reference point S and T;
(ISO/IEC 8877: 1992)".
[6] CCITT Recommendation G.117 (1988): "Transmission aspects of unbalance
about earth (definitions and methods)".
[7] ETS 300 102-1 (1990): "Integrated Services Digital Network (ISDN);
User-network interface layer 3; Specifications for basic call control".
[8] ETS 300 012-1 (1998): "Integrated Services Digital Network (ISDN); Basic User
Network Interface (UNI); Part 1: Layer 1 specification".
[9] ITU-T Recommendation X.200 (1994): "Information technology; Open Systems
Interconnection; Basic reference model: The basic model".
[10] ITU-T Recommendation Q.512 (1995): "Digital exchange interfaces for
subscriber access".
[11] CCITT Recommendation G.812 (1988): "Timing requirements at the outputs of
slave clocks suitable for plesiochronous operation of international digital links".

---------------------- Page: 9 ----------------------

SIST ETS 300 012-5 E2:2003
Page 8
ETS 300 012-5: October 1998
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of this ETS the following definitions, together with those given in annex E of
ITU-T Recommendation I.430 [1] and in ITU-T Recommendation I.411 [2] apply.
basic access: A user-network access arrangement that corresponds to the interface structure composed
of two B-channels and one D-channel. The bit rate of the D-channel for this type of access is 16 kbit/s.
B-channel: This function provides for the bi-directional transmission of independent B-channel signals
each having a bit rate of 64 kbit/s.
bearer service: A type of telecommunication service that provides the capability for the transmission of
signals between UNI.
NOTE 1: The ISDN connection type used to support a bearer service may be identical to that
used to support other types of telecommunication service.
connection management entity: An entity for the purpose of management of resources that have an
impact on an individual data link connection.
D-channel: This function provides for bi-directional transmission of one D-channel signal at a bit rate of
16 kbit/s.
designated terminal: A terminal which is permitted to draw power from power source 1 under both
normal and restricted power conditions.
frame alignment: This function provides information to enable the TE or NT to recover the time-division
multiplexed channels.
Integrated Services Digital Network (ISDN): A network that provides or supports a range of different
telecommunications services and provides digital connections between UNIs.
interface I : User side of the ISDN UNI for the basic access.
A
interface I : Network side of the ISDN UNI for the basic access.
B
IUT (Implementation Under Test): Interface point I i.e. NT2 or access connection element (see also
B
ITU-T Recommendation I.430 [1], annex E, clause E.1 definition 109).
Network Termination (NT): An equipment providing interface I .
B
NOTE 2: This term is used in this ETS to indicate network-terminating aspects of NT1, NT2 and
PS1 functional groups where these have an I interface.
B
Network Termination Type 1 (NT1): This functional group includes functions broadly equivalent to
layer 1 (physical) of the Open Systems Interconnection (OSI) reference model. These functions are
associated with the proper physical and electromagnetic termination of the network. NT1 functions are:
- line transmission termination;
- layer 1 maintenance functions and performance monitoring;
- timing;
- power transfer;
- layer 1 multiplexing;
- interface termination, including multidrop termination;
- employing layer 1 contention resolution.

---------------------- Page: 10 ----------------------

SIST ETS 300 012-5 E2:2003
Page 9
ETS 300 012-5: October 1998
Network Termination Type 2 (NT2): This functional group includes functions broadly equivalent to
layer 1 and higher layers of the ITU-T Recommendation X.200 [9] reference model. Private Automatic
Branch Exchanges (PABXs), Local Area Networks (LANs), and terminal controllers are examples of
equipment or combinations of equipment that provide NT2 functions. NT2 functions include:
- layer 2 and 3 protocol handling;
- layer 2 and 3 multiplexing;
- switching;
- concentration;
- maintenance functions;
- interface termination and other layer 1 functions.
non-designated terminal: A terminal which is only permitted to draw power from power source 1 under
normal power conditions.
normal power condition: The condition indicated by the normal polarity of the phantom voltage at the
access leads, i.e. where the voltage of the transmit leads c and d on the TE is positive with respect to the
voltage on the receive leads e and f.
Power Source 1 (PS1): Power source for the provision of remote power feeding of TE via a phantom
circuit of the interface wires.
Rx (Receiver): Interface signal receiver of IUT or simulator.
restricted power condition: The condition indicated by the reversed polarity of the phantom voltage at
the access leads, i.e. where the voltage of the receive leads e and f on the TE is positive with respect to
the voltage on the transmit leads c and d.
simulator: Device generating the stimulus signal for the IUT and monitoring the signal transmitted by the
IUT to test the characteristics of NT.
Terminal Adapter (TA): An equipment with interface I and one or more auxiliary interfaces that allow
A
non-ISDN terminals to be served by an ISDN UNI (see also ITU-T Recommendation I.411 [2]).
Terminal Equipment (TE): An equipment with interface I and consisting of one or more functional
A
blocks.
NOTE 3: This term is used in this ETS to indicate terminal-terminating aspects of TE1, TA and
NT2 functional groups, where these have an I interface.
A
Terminal Equipment Type 1 (TE1): This functional group includes functions belonging to the functional
group TE, and with an interface that complies with the ISDN UNI recommendation.
Tx (Transmitter): Interface signal transmitter of IUT or simulator.
3.2 Symbols
For the purposes of this ETS, the following symbols apply:
ONE Binary "1"
ZERO Binary "0"
3.3 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
APS Auxiliary Power Supply
dc direct current
ETS European Telecommunication Standard
I Informative
I Interface point A
A
I Interface point B
B

---------------------- Page: 11 ----------------------

SIST ETS 300 012-5 E2:2003
Page 10
ETS 300 012-5: October 1998
ICS Implementation Conformance Statement
ISDN Integrated Services Digital Network
IUT Implementation Under Test
IXIT Implementation eXtra Information for Testing
LCL Longitudinal Conversion Loss
N Normative
N/R Not Relevant
NT Network Termination
ppm parts per million
PS1 Power Source 1
Rx Receive
Tx Transmit
UI Unit Interval (Layer 1)
4 Allocation of tests
4.1 Scope
Scope Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Scope 1 N/R
4.2 References
Scope Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
References 2 N/R
4.3 Definitions, symbols and abbreviations
Definitions, symbols and abbreviations Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Definitions, symbols and abbreviations 3 N/R
Definitions 3.1 N/R
General definitions 3.1.1 N/R
Interface 3.1.1.1 N/R
NT 3.1.1.2 N/R
TE 3.1.1.3 N/R
Definition of services 3.1.2 N/R
Services required from the physical medium 3.1.2.1 N/R
Services provided to layer 2 3.1.2.2 N/R
Transmission capability 3.1.2.2.1 N/R
Activation/deactivation 3.1.2.2.2 N/R
D-channel access 3.1.2.2.3 N/R
Maintenance 3.1.2.2.4 N/R
Status indication 3.1.2.2.5 N/R
Primitives between layer 1 and other entities 3.1.3 N/R
Modes of operation 3.1.4 N/R
Point-to-point operation 3.1.4.1 N/R
Point-to-multipoint operation 3.1.4.2 N/R
Definitions of states 3.1.5 N/R

---------------------- Page: 12 ----------------------

SIST ETS 300 012-5 E2:2003
Page 11
ETS 300 012-5: October 1998
TE states 3.1.5.1 N/R
State F1 (inactive) 3.1.5.1 N/R
State F2 (sensing) 3.1.5.1 N/R
State F3 (deactivated) 3.1.5.1 N/R
State F4 (awaiting signal) 3.1.5.1 N/R
State F5 (identifying input) 3.1.5.1 N/R
State F6 (synchronized) 3.1.5.1 N/R
State F7 (activated) 3.1.5.1 N/R
State F8 (lost framing) 3.1.5.1 N/R
NT states 3.1.5.2 N/R
State G1 (deactive) 3.1.5.2 6.3.1
State G2 (pending activation) 3.1.5.2 6.3.1
State G3 (active) 3.1.5.2 6.3.1
State G4 (pending deactivation) 3.1.5.2 6.3.1
Symbols 3.2 N/R
Abbreviations 3.3 N/R
4.4 Primitives associated with layer 1
Primitives associated with layer 1 Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Primitives associated with layer 1 4 N/R
4.5 Wiring configurations and location of interface points
Modes Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Wiring configurations and location of interface points 5 N/R
General 5.1 N/R
Point-to-point configuration 5.1.1 N/R
Point-to-multipoint configuration 5.1.2 N/R
Location of the interfaces 5.1.3 N/R
Support of wiring configurations 5.2 N/R
Wiring polarity integrity 5.2.1 6.3.2.1.1
NT and TE associated wiring 5.2.2 N/R
4.6 Functional characteristics
Functions Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Functional characteristics 6 N/R
Interface functions 6.1 N/R
B-channel 6.1.1 5.1
Bit timing 6.1.2 5.1.1
Octet timing 6.1.3 5.1.1
Frame alignment 6.1.4 6.4
D-channel 6.1.5 5.1.1
D-channel access procedure 6.1.6 6.2
Power feeding 6.1.7 8
Deactivation 6.1.8 6.3.3
Activation 6.1.9 6.3.3
Interchange circuits 6.2 5.2.1

---------------------- Page: 13 ----------------------

SIST ETS 300 012-5 E2:2003
Page 12
ETS 300 012-5: October 1998
Connected/disconnected indication 6.3 N/R
TEs powered across the interface 6.3.1 N/R
TEs not powered across the interface 6.3.2 N/R
Indication of connection status 6.3.3 N/R
Line code 6.4 5.1.1
Frame structure 6.5 5.1
Bit rate 6.5.1 5.1.1
Binary organization of the frame 6.5.2 N/R
TE to NT 6.5.2.1 N/R
NT to TE 6.5.2.2 5.1
Timing considerations 6.6 5.1.1
4.7 Interface procedures
D-channel access Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Interface procedures 7 N/R
D-channel access procedure 7.1 N/R
Interframe (layer 2) time fill 7.1.1 6.1
D-echo channel 7.1.2 6.2
D-channel monitoring 7.1.3 N/R
Priority mechanism 7.1.4 N/R
Collision detection 7.1.5 N/R
Activation/deactivation Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Activation/deactivation 7.2 N/R
Activate primitives 7.2.1 6.3
Deactivate primitives 7.2.2 6.3
Management primitives 7.2.3 6.3
Valid primitive sequences 7.2.4 N/R
Signals 7.3 5.1.1, 5.1.2
Activation/deactivation procedure for TEs 7.4 6.3.1
General TE procedures 7.4.1 N/R
Specification of the procedures 7.4.2 N/R
Activation/deactivation for NTs 7.5 6.3
Non-activating/non-deactivating NTs 7.5.1 6.3
Timer values 7.6 6.3.2.3
Activation times 7.7 N/R
TE activation times 7.7.1 N/R
NT activation times 7.7.2 6.3.2.1, 6.3.2.2
Deactivation times 7.8 6.3.2.2
Frame alignment Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Frame alignment procedures 8 6.4
Frame alignment procedure in the direction NT to TE 8.1 N/R
Loss of frame alignment 8.1.1 N/R
Frame alignment 8.1.2 N/R
Frame alignment in the direction TE to NT 8.2 6.4
Loss of frame alignment 8.2.1 6.4
Frame alignment 8.2.2 6.4
Multi-framing 8.3 N/R
Idle channel code on the B-channels 8.4 N/R

---------------------- Page: 14 ----------------------

SIST ETS 300 012-5 E2:2003
Page 13
ETS 300 012-5: October 1998
4.8 Electrical characteristics
Functions Clause / Test defined in
subclause in clause / subclause
ETS 300 012-1 [8]
this ETS
Electrical characteristics 9 N/R
Bit rate 9.1 7.1
Nominal rate 9.1.1 7.1.1, 7.1.2
Tolerance 9.1.2 7.1.1, 7.1.2
Jitter and bit-phase relationship between TE input and output 9.2 N/R
Test configurations 9.2.1 N/R
Timing extraction jitter 9.2.2 N/R
Total phase deviation input to output 9.2.3 N/R
NT jitter characteristics 9.3 7.2
Termination of the line 9.4 N/R
Transmitter output characteristics 9.5 N/R
Transmitter output impedance 9.5.1 N/R
NT transmitter output impedance 9.5.1.1 7.3
TE transmitter output impedance 9.5.1.2 N/R
Test load impedance 9.5.2 N/R
Pulse shape and amplitude (binary ZERO) 9.5.3 7.4
Pulse shape 9.5.3.1 7.4
Nominal pulse amplitude 9.5.3.2 7.4
Pulse unbalance 9.5.4 N/R
Pulse amplitude when transmitting a high density pattern 9.5.4.1 7.5.1
Pulse unbalance of an isolated couple of pulses 9.5.4.2 7.5.2
Voltage on other test loads (TE only) 9.5.5 N/R
400 W load 9.5.5.1 N/R
9.5.5.2 N/R
5,6 W load
Unbalance about earth 9.5.6 7.6
Longitudinal conversion loss 9.5.6.1 7.6
Output signal balance 9.5.6.2 N/R
Receiver input characteristics 9.6 N/R
Receiver input impedance 9.6.1 N/R
TE receiver input impedance 9.6.1.1 N/R
NT receiver input impedance 9.6.1.2 7.7.1
Receiver sensitivity - Noise and distortion immunity 9.6.2 7.7.2
TEs 9.6.2.1 N/R
NTs for short passive bus (fixed timing) 9.6.2.2 7.7.2
NTs for both point-to-point and short passive bus 9.6.2.3 7.7.2
configurations (adaptive timing)
NTs for extended passive bus wiring configurations 9.6.2.4 7.7.2
NTs for point-to-point configurations only 9.6.2.5 7.7.2
NT receiver input delay characteristics 9.6.3 7.7.3
NT for short passive bus 9.6.3.1 7.7.3
NT for both point-to-point and passive bus 9.6.3.2 7.7.3
NT for extended passive bus 9.6.3.3 7.7.3
NT for point-to-point only 9.6.3.4 7.7.3
Unbalance about earth 9.6.4 7.7.4
Isolation from external
...