SIST ETS 300 766 E1:2005

• Abstract:

  Specification of the public network interface and test methods for compliance.

• Status: Published
• Publication Date: 31-Jan-2005
• ICS: 33.040.50 - Lines, connections and circuits
• Technical Committee: RES - Radio equipment and systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Feb-2005
• Due Date: 01-Feb-2005
• Completion Date: 01-Feb-2005
• Mandate: T-307
• Ref Project: ETSI ETS 300 766 ed.1 (1998-03) - Business TeleCommunications (BTC); Multiple 64 kbit/s digital unrestricted leased lines with octet integrity presented at a structured 2 048 kbit/s interface at either or both ends (D64M); Connection characteristics and network interface presentation

SIST ETS 300 766 E1:2005 is the Slovenian adoption of ETS 300 766 Edition 1 for Business TeleCommunications (BTC). It specifies the technical requirements, public network interface presentation, and compliance test principles for multiple 64 kbit/s digital unrestricted leased lines with octet integrity when they are presented at a structured 2 048 kbit/s interface at either or both ends.

What does SIST ETS 300 766 E1:2005 specify?

SIST ETS 300 766 E1:2005 specifies the public network interface and connection characteristics for a point-to-point 64 kbit/s digital unrestricted leased line with octet integrity. The line may run between two 2 048 kbit/s structured interfaces, or between a 2 048 kbit/s structured interface and a 64 kbit/s co-directional interface.

The standard applies to leased lines, including part-time leased lines, whose establishment or release does not require protocol exchange or other intervention at the Network Termination Point (NTP). It covers the network side of the service, not terminal equipment.

The document is organized into clauses on scope, normative references, definitions and abbreviations, an informative overview, connection characteristics, interface characteristics for the 2 048 kbit/s interface, interface characteristics for the 64 kbit/s interface, safety, and EMC. It also includes a normative annex on test methods and an informative bibliography.

Annex	What it covers
Annex A	Normative test methods, including test configuration, stimulus, monitoring, and result criteria
Annex B	Informative bibliography and related directives, recommendations, and standards

What are the key requirements of SIST ETS 300 766 E1:2005?

SIST ETS 300 766 E1:2005 defines a set of service and interface attributes that the leased line has to meet, together with the test approach used to verify them. In practice, it tells a provider what the line must carry, how octets must be preserved, and which inherited interface requirements from the 64 kbit/s and 2 048 kbit/s base standards apply.

Connection characteristics

Clause 5 sets the service characteristics. The leased line must support a nominal 64 kbit/s information transfer rate, unrestricted digital information, separate octets, symmetry in both directions, and point-to-point communication.

Clause 5 also ties the service to performance attributes: transmission delay, jitter, controlled slip, errored seconds, and severely errored seconds. For users, this is the part that defines whether the line is suitable for transparent digital transport rather than traffic that can tolerate rearrangement or protocol handling.

Octet integrity and structure

Clause 5.4 is central to this standard. The leased line must pass each octet in order and present it as a complete octet at the output, with bit order and octet order preserved. Where the output is a 2 048 kbit/s interface, the octet must stay within one time slot.

This matters because the service is intended for digital traffic that depends on octet boundaries. If the line maps traffic between 64 kbit/s and 2 048 kbit/s presentations, the start bit of the assigned time slot and the first bit of each octet must align correctly.

2 048 kbit/s interface presentation

Clause 6 applies when the leased line is presented at a 2 048 kbit/s interface. The interface must follow the frame structure, CRC-4 behavior, E-bit use, frame synchronization, multiframe alignment, output signal coding, waveform shape, timing, jitter, return loss, loss tolerance, reflection immunity, longitudinal voltages, ground impedance, and input jitter tolerance requirements referenced from ETS 300 418 and ETS 300 419.

In practice, this means implementers use the established 2 048 kbit/s interface rules and then apply the leased-line-specific time slot assignment. The same time slot is used in both directions, and the line provider and user should agree on the assigned slot.

64 kbit/s interface presentation

Clause 7 applies when the leased line is presented at a 64 kbit/s interface. It reuses the connection arrangement, coding, waveform, timing, jitter, impedance, return loss, loss tolerance, reflection immunity, and longitudinal conversion loss requirements referenced from ETS 300 288 and ETS 300 289.

For users, this means a 64 kbit/s end of the service must behave like the established D64U interface, with the leased line-specific behavior preserved across the 2 048 kbit/s structured side when present.

Testing and compliance

Annex A provides the normative test methods. The main test in A.2 verifies information transfer rate, unrestricted digital transfer, symmetry, frame structure, octet integrity, and CRC-4 using a 2 048 kbit/s loopback arrangement. The test stimulus uses a PRBS pattern and also includes runs of zeros and ones.

Clause 5 also adapts tests for controlled slip, errored seconds, and severely errored seconds when the service is presented at a 2 048 kbit/s interface. That is important for acceptance testing and type testing, because it shows how to check the leased line behavior without rewriting the inherited 64 kbit/s and 2 048 kbit/s test methods from scratch.

Safety and EMC

Clause 8 requires compliance with SELV accessible-part requirements and sets a touch current limit of 0.25 mA across the leased line interface. Clause 9 states that there are no EMC requirements under this ETS.

For equipment suppliers, that means the interface must be treated as a safety-controlled network interface, while EMC obligations come from the wider regulatory environment rather than from this ETS itself.

What terms does SIST ETS 300 766 E1:2005 define?

SIST ETS 300 766 E1:2005 defines the terminology it uses so that interface behavior and test results are interpreted consistently.

• Network Termination Point (NTP) - The physical network access point and its technical access specifications that form part of the public telecommunications network.
• leased lines - Telecommunications facilities that provide defined transmission characteristics between NTPs without user-controlled switching.
• frame - A sequence of 256 bits in which the first 8 bits define the frame structure.
• octet slip - A slip of one complete octet.
• errored second - A second with one or more bit errors.
• severely errored second - A second in which at least 0.1% of the bits are in error.
• PRBS (Pseudo Random Bit Sequence) - A test bit sequence defined by CCITT Recommendation O.151 or O.152, used as a stimulus in compliance tests.
• SELV (Safety Extra-Low Voltage) circuit - A protected circuit designed so accessible voltages stay within a safe value under normal and single-fault conditions.

Who uses SIST ETS 300 766 E1:2005?

SIST ETS 300 766 E1:2005 is used by public telecommunications network operators, leased-line providers, and equipment suppliers that implement the NTP or the interface presentation. It is also used by test laboratories and conformity assessors that need a defined method for checking compliance.

Network planners and buyers use it to understand what kind of leased line is being offered and what interface behavior to expect. Terminal equipment designers use it alongside the related D64U and D2048S interface standards to match equipment to the correct network presentation.

What changed in SIST ETS 300 766 E1:2005 from the previous edition?

SIST ETS 300 766 E1:2005 corresponds to ETS 300 766 Edition 1.

Which standards are used with SIST ETS 300 766 E1:2005?

SIST ETS 300 766 E1:2005 builds on a small set of referenced standards and related BTC parts.

• ETS 300 288 - Provides the 64 kbit/s D64U network interface presentation requirements used in Clause 7.
• ETS 300 289 - Provides the 64 kbit/s D64U connection characteristics used in Clause 5 and several test methods.
• ETS 300 418 - Provides the 2 048 kbit/s network interface presentation requirements used in Clause 6.
• ETS 300 419 - Provides the 2 048 kbit/s structured leased-line connection characteristics used in Clause 5 and the adapted tests.
• EN 60950 - Provides the safety requirements used for the SELV-related tests in Clause 8.
• ETS 300 046-4 - Provides the touch-current test approach used in Clause 8.2.
• CCITT Recommendation I.410 - Provides the attribute technique referenced for describing connection characteristics.
• CCITT Recommendation O.151 and O.152 - Define PRBS patterns used in the test methods.

The foreword also identifies related BTC standards for D64U and D2048S terminal equipment and interface presentation, which help users combine this ETS with the surrounding leased-line family.

What does the SIST ETS 300 766 E1:2005 document contain?

SIST ETS 300 766 E1:2005 contains a clause-by-clause technical specification, not just a short interface summary. Clause 5 gives the service attributes and their compliance tests, while Clauses 6 and 7 give the inherited electrical and functional requirements for the 2 048 kbit/s and 64 kbit/s interfaces.

Annex A gives the test configurations, including loopback arrangements, stimulus signals, monitoring points, and result criteria. It is the part readers will use for design verification, type testing, and compliance checking of interface equipment.

The document also includes an informative overview with an example of how multiple 64 kbit/s leased lines can share a 2 048 kbit/s interface, plus an informative bibliography in Annex B for the related directives, Recommendations, and ETSs.

SLOVENSKI STANDARD
01-februar-2005
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Business TeleCommunications (BTC); Multiple 64 kbit/s digital unrestricted leased lines
with octet integrity presented at a structured 2 048 kbit/s interface at either or both ends
(D64M); Connection characteristics and network interface presentation
Ta slovenski standard je istoveten z: ETS 300 766 Edition 1
ICS:
33.040.50 Vodi, zveze in tokokrogi Lines, connections and
circuits
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 766
TELECOMMUNICATION March 1998
STANDARD
Source: BTC Reference: DE/BTC-02067
ICS: 33.020
Key words: Digital, interface, leased line, ONP, testing
Business TeleCommunications (BTC);
Multiple 64 kbit/s digital unrestricted leased lines with octet
integrity presented at a structured 2 048 kbit/s interface
at either or both ends (D64M);
Connection characteristics and network interface presentation
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.

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ETS 300 766: March 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 Editing and Committee Support Dept." at the address shown on the title page.

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ETS 300 766: March 1998
Contents
Foreword .5
Introduction.5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .8
3.1 Definitions .8
3.2 Abbreviations .9
4 Overview (informative) .9
5 Connection characteristics .10
5.1 Summary of attributes.10
5.2 Information transfer rate .11
5.3 Information transfer susceptance .11
5.4 Structure and octet integrity .11
5.5 Establishment of connection.12
5.6 Symmetry.12
5.7 Transmission delay.12
5.8 Controlled slip .13
5.9 Errored seconds .13
5.10 Severely errored seconds.13
5.11 Availability .13
6 Interface characteristics - 2 048 kbit/s interface.13
6.1 Connection arrangements .13
6.2 Frame structure .14
6.2.1 General.14
6.2.2 2 048 kbit/s digital structured ONP leased line (CRC-4) .14
6.2.3 Use of the E-bits.14
6.2.4 Frame synchronization and data transmission capability.14
6.2.5 Multiframe alignment.14
6.3 Output signal coding .14
6.4 Output waveform shape.15
6.5 Output timing.15
6.6 Output timing under failure conditions .15
6.7 Output impedance towards ground.15
6.8 Output jitter .15
6.9 Input signal coding.15
6.10 Input return loss .15
6.11 Input loss tolerance.15
6.12 Input immunity against reflections .15
6.13 Tolerable longitudinal voltages .16
6.14 Impedance towards ground .16
6.15 Input jitter tolerance .16
7 Interface characteristics - 64 kbit/s interface.16
7.1 Connection arrangements .16
7.2 Output signal coding and octet structure .16
7.3 Output waveform shape.16
7.4 Output timing.16
7.5 Output timing under failure conditions .16
7.6 Output jitter .17

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ETS 300 766: March 1998
7.7 Impedance towards ground. 17
7.8 Longitudinal conversion loss . 17
7.9 Input signal coding and octet structure . 17
7.10 Input jitter tolerance. 17
7.11 Input return loss. 17
7.12 Input loss tolerance . 17
7.13 Immunity against reflections. 17
7.14 Impedance towards ground. 17
7.15 Longitudinal conversion loss . 18
8 Safety. 18
8.1 General requirements . 18
8.2 Touch current . 18
9 ElectroMagnetic Compatibility (EMC) . 18
Annex A (normative): Test methods. 19
A.1 General. 19
A.1.1 Additional information to support the test. 19
A.1.2 Equipment connection.19
A.2 Main test . 19
Annex B (informative): Bibliography . 21
History. 22

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ETS 300 766: March 1998
Foreword
This European Telecommunication Standard (ETS) has been produced by the Business
TeleCommunications (BTC) Technical Committee of the European Telecommunications Standards
Institute (ETSI).
This ETS resulted from a mandate from the Commission of the European Community (CEC) to provide
harmonized standards for the support of the Directive on Open Network Provision (ONP) of leased lines
(92/44/EEC).
There are six other standards directly related to this ETS:
ETS 300 288: "Business TeleCommunications (BTC); 64 kbit/s digital unrestricted leased line with octet
integrity (D64U); Network interface presentation";
ETS 300 289: "Business TeleCommunications (BTC); 64 kbit/s digital unrestricted leased line with octet
integrity (D64U); Connection characteristics";
ETS 300 290: "Business TeleCommunications (BTC); 64 kbit/s digital unrestricted leased line with octet
integrity (D64U); Terminal equipment interface";
ETS 300 418 (1995): "Business TeleCommunications (BTC); 2 048 kbit/s digital unstructured and
structured leased lines (D2048U and D2048S); Network interface presentation".
ETS 300 419 (1995): "Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased lines
(D2048S); Connection characteristics".
ETS 300 420 (1995): "Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased lines
(D2048S); Terminal equipment interface".
This ETS is based on information from CCITT Recommendations and ETSI publications and the relevant
documents are quoted where appropriate.
This ETS has been written as a "delta" document to the existing standards for 64 kbit/s and 2 048 kbit/s
leased lines. It uses requirements from these standards by cross reference with modifications as
necessary to the test. The configurations covered by this ETS could have been addressed by modifying
the existing standards for 64 kbit/s and 2 048 kbit/s leased lines to make them more modular so that the
64 kbit/s connection characteristics could be used in conjunction with the 2 048 kbit/s structured interface.
In some ways this would have been a tidier solution, but it would involve considerable additional activity
because the existing standards for 64 kbit/s and 2 048 kbit/s leased lines are currently the subject of
regulation and references to them in the annex of the ONP leased line Directive would have to be
changed.
Transposition dates
Date of adoption of this ETS: 6 March 1998
Date of latest announcement of this ETS (doa): 30 June 1998
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 December 1998
Date of withdrawal of any conflicting National Standard (dow): 31 December 1998
Introduction
The Council Directive on the application of ONP to leased lines (92/44/EEC) concerns the harmonization
of conditions for open and efficient access to, and use of, the leased lines provided over public
telecommunications networks and the availability throughout the European Union (EU) of a minimum set
of leased lines with harmonized technical characteristics.

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ETS 300 766: March 1998
Other countries outside the EU may also choose to provide leased lines according to the standards
produced to support the Directive.
The consequence of the Directive is that telecommunications organizations within the EU shall make
available a set of leased lines between points in these countries with specified connection characteristics
and specified interfaces. Under the Second Phase Directive (91/263/EEC), Terminal Equipment (TE)for
connection to these leased lines will be required to fulfil certain essential requirements.
The leased line specified in this ETS is not included in the minimum set whose provision is required under
Directive 92/44/EEC, however this standard is written as a "delta" document based on the specifications
for the 2 048 kbit/s digital structured ONP leased line (D2048S) and 64 kbit/s digital unrestricted ONP
leased line with octet integrity (D64U) leased lines.
ETS 300 166 and CCITT Recommendation G.703 are used as the basis for the interface presentation
requirements. ETS 300 167, CCITT Recommendations G.704 and G.706 are used as the basis for the
structure of the 2 048 kbit/s interface.
This ETS does not apply to terminal equipment. ETS 300 290 applies without modification to TE intended
for connection to the 64 kbit/s interface of the leased line. In theory ETS 300 420 should be modified to
define the time slot structure for terminals intended for connection to 2 048 kbit/s interfaces that present
64 kbit/s leased lines. However, the modification is too trivial to be worth implementing.

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ETS 300 766: March 1998
1 Scope
This European Telecommunication Standard (ETS) specifies the technical requirements and test
principles for the connection characteristics and network interface presentations of a 64 kbit/s
-
point-to point digital unrestricted leased line with octet integrity that is provided between either:
- two 2 048 kbit/s structured network interfaces; or
- a 2 048 kbit/s structured network interface and a 64 kbit/s co-directional network interface.
More than one leased line of the type described in this ETS may be provided at any 2 048 kbit/s network
interface. Such leased lines may connect to the same or different destinations.
This ETS is written as a "delta" document based on the following ETSs:
- ETS 300 288: "Business TeleCommunications (BTC); 64 kbit/s digital unrestricted leased line with
octet integrity (D64U); Network interface presentation". [1]
- ETS 300 289: "Business TeleCommunications (BTC); 64 kbit/s digital unrestricted leased line with
octet integrity (D64U); Connection characteristics". [2]
- ETS 300 418: "Business TeleCommunications (BTC); 2 048 kbit/s digital unstructured and
structured leased lines (D2048U and D2048S); Network interface presentation". [3]
- ETS 300 419: "Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased lines
(D2048S); Connection characteristics". [4]
This ETS is applicable to leased lines, including part time leased lines, whose establishment or release
does not require any protocol exchange or other intervention at the Network Termination Point (NTP).
This ETS covers the connection characteristics, and the mechanical and electrical characteristics of the
network interface, and specifies conformance tests. Some of the tests for the interface presentation
described in this ETS are not designed to be applied to the interface of an installed leased line; such tests
may be applied to equipment of the kind used to provide the interface. This ETS does not include details
concerning the implementation of the tests nor does it include information on any regulations concerning
testing.
NOTE: There is no requirement for each leased line to be tested in accordance with this ETS
before it is brought into, or returned into, service.
2 Normative references
This ETS incorporates by dated or 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] ETS 300 288 (1994) including Amendment 1 (1995): "Business
TeleCommunications (BTC); 64 kbit/s digital unrestricted leased line with octet
integrity (D64U); Network interface presentation".
[2] ETS 300 289 (1994): "Business TeleCommunications (BTC); 64 kbit/s digital
unrestricted leased line with octet integrity (D64U); Connection characteristics".
[3] ETS 300 418 (1995): "Business TeleCommunications (BTC); 2 048 kbit/s digital
unstructured and structured leased lines (D2048U and D2048S); Network
interface presentation".
[4] ETS 300 419 (1995): "Business TeleCommunications (BTC); 2 048 kbit/s digital
structured leased lines (D2048S); Connection characteristics".

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ETS 300 766: March 1998
[5] EN 60950: "Safety of information technology equipment, including electrical
business equipment".
[6] ETS 300 046-4 (1992): "Integrated Services Digital Network (ISDN); Primary
rate access - safety and protection, Part 4: Interface Ib - safety".
[7] CCITT Recommendation I.410 (1988): "General aspects and principles relating
to Recommendations on ISDN user-network interfaces".
[8] CCITT Recommendation O.151 (1992): "Error performance measuring
equipment operating at the primary rate and above".
[9] CCITT Recommendation O.152 (1988): "Error performance measuring
equipment for bit rates of 64 kbit/s and N · 64 Kbits/s"
NOTE: This ETS also contains a number of informative references which have been included
to indicate the sources from which various material has been derived, hence they do
not have an associated normative reference number. Details of these publications are
given in annex B. In some cases the same publication may have been referenced in
both a normative and an informative manner.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
errored second: A second with one or more bit errors.
frame: a sequence of 256 bits of which the first 8 bits define the frame structure
leased lines: The telecommunications facilities provided by a public telecommunications network that
provide defined transmission characteristics between network termination points and that do not include
switching functions that the user can control (e.g. on-demand switching).
Network Termination Point (NTP): All physical connections and their technical access specifications
which form part of the public telecommunications network and are necessary for access to and efficient
communication through that public network.
octet slip: a slip of one complete octet.
PRBS(2 -1): A Pseudo Random Bit Sequence (PRBS) as defined in subclause 2.1 of CCITT
Recommendation O.151 [8].
PRBS(2 -1): A Pseudo Random Bit Sequence (PRBS) as defined in subclause 2.1 of CCITT
Recommendation O.152 [9].
Safety Extra-Low Voltage (SELV) circuit: A secondary circuit which is so designed and protected that
under normal and single fault conditions, the voltage between any two accessible parts and, for class 1
equipment, between any accessible part and the equipment protective earthing terminal does not exceed
a safe value (subclause 1.2.8.5 of EN 60950 [5]).
severely errored second: A second where at least 0,1 % of the bits are errored.
slip: One or more extra or missing consecutive unit intervals in the bit stream.
time slot: In the context of this ETS, a time slot is a period of nominally 3,90625 ms (8 bits). Each frame of
nominally 125 ms is subdivided into 32 time slots numbered 0-31.
terminal equipment: Equipment intended to be connected to the public telecommunications network, i.e.:

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ETS 300 766: March 1998
- to be connected directly to the termination of a public telecommunication network; or
- to interwork with a public telecommunications network being connected directly or indirectly to the
termination of a public telecommunications network, in order to send, process, or receive
information.
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
CRC-4 Cyclic Redundancy Check (using four bits)
D2048S 2 048 kbit/s digital structured ONP leased line
D64M Multiple 64 kbit/s digital unrestricted leased lines with octet integrity at a
structured 2 048 kbit/s interface at either or both ends
D64U 64 kbit/s digital unrestricted ONP leased line with octet integrity
EMC ElectroMagnetic Compatibility
NTP Network Termination Point
ONP Open Network Provision
PRBS Pseudo Random Bit Sequence
SELV Safety Extra-Low Voltage
TE Terminal Equipment
4 Overview (informative)
This ETS applies to 64 kbit/s leased lines where at least one end is presented in a 2 048 kbit/s interface.
This includes leased lines in a wide variety of cases and configurations such as:
- a number of 64 kbit/s leased lines presented in a single 2 048 kbit/s interface at one location but
each connecting to a different location;
- a single 64 kbit/s leased line presented in a single 2 048 kbit/s interface at each end where other
time slots in the interfaces are used for other services;
- a number of 64 kbit/s leased lines between the same 2 048 kbit/s interfaces. In this case there is no
guarantee that the leased lines will follow the same route and have the same transmission delay,
i.e. octets of data that share the same frame at the input will not necessarily share the same frame
at the output. An example is shown in figure 1.
2 048 kbit/s interface
2 048 kbit/s interface
NTP
NTP
64 kbit/s interface
NTP
64 kbit/s interface
NTP
Figure 1
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ETS 300 766: March 1998
Where there are 64 kbit/s leased lines to different destinations, each of the leased lines is point-to-point;
there is no broadcasting or point-to-multipoint capability.
This ETS has been written as a "delta" document to the existing standards for 64 kbit/s and 2 048 kbit/s
leased lines. It uses requirements from these standards by cross reference with modifications as
necessary to the test. The configurations covered by this ETS could have been addressed by modifying
the existing standards for 64 kbit/s and 2 048 kbit/s leased lines to make them more modular so that the
64 kbit/s connection characteristics could be used in conjunction with the 2 048 kbit/s structured interface.
In some ways this would have been a tidier solution, but it would involve considerable additional activity
because the existing standards for 64 kbit/s and 2 048 kbit/s leased lines are currently the subject of
regulation and references to them in the annex of the ONP leased line Directive would have to be
changed.
5 Connection characteristics
The performance of the leased line shall comply with the requirements of this clause, only if the conditions
of supply of the network equipment that provides the NTP are met, (e.g. if the equipment is connected to
an appropriate power supply on the customer's premises).
The ITU-T attribute technique is used to express the connection requirements. The following attributes
from CCITT Recommendation I.140 [7] are considered relevant for this ETS:
- information transfer rate;
- information transfer susceptance;
- structure;
- establishment of connection;
- symmetry;
- network performance.
NOTE: "Bit rate
...