ETSI EN 300 690 V1.2.1 (2001-07)

SLOVENSKI STANDARD
01-oktober-2004
Dostop in terminali (AT) - Digitalni zakupljeni vodi za prenosno hitrost 140 Mbit/s
(D140U, D140S) - Vmesnik terminalske opreme
Access and Terminals (AT); 140 Mbit/s digital leased lines (D140U and D140S);
Terminal equipment interface
Ta slovenski standard je istoveten z: EN 300 690 Version 1.2.1
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 Standard (Telecommunications series)
Access and Terminals (AT);
140 Mbit/s digital leased lines (D140U and D140S);
Terminal equipment interface
2 ETSI EN 300 690 V1.2.1 (2001-07)
Reference
REN/AT-020010
Keywords
access, digital, interface, leased line, ONP,
terminal
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© European Telecommunications Standards Institute 2001.
All rights reserved.
ETSI
3 ETSI EN 300 690 V1.2.1 (2001-07)
Contents
Intellectual Property Rights .5
Foreword.5
Introduction.6
1 Scope.7
2 References.7
3 Definitions and abbreviations.8
3.1 Definitions . 8
3.2 Abbreviations. 8
4 Requirements.9
4.1 Mechanical characteristics. 9
4.1.1 Sockets . 10
4.1.2 Plugs . 10
4.2 Electrical characteristics . 10
4.2.1 Output port . 10
4.2.1.1 Signal coding. 10
4.2.1.2 Waveform shape. 11
4.2.1.3 Output timing . 12
4.2.1.4 Output return loss . 13
4.2.1.5 Output jitter. 13
4.2.1.6 Output frame structure. 13
4.2.2 Input port. 13
4.2.2.1 Signal coding. 13
4.2.2.2 Input return loss. 14
4.2.2.3 Input loss tolerance. 14
4.2.2.4 Input jitter tolerance. 14
4.2.2.5 Input clock tolerance. 15
4.2.2.6 Input frame structure. 15
4.2.2.7 Frame alignment procedure. 15
4.3 Safety. 16
4.4 Overvoltage. 16
4.5 ElectroMagnetic Compatibility (EMC) . 16
Annex A (normative): Test methods .17
A.1 General.17
A.1.1 Additional information to support the test . 17
A.1.2 Equipment connection . 17
A.2 Test methods .18
A.2.1 Signal coding at the output port . 18
A.2.2 Waveform shape at the output port. 18
A.2.3 Output timing. 19
A.2.4 Input signal coding and loss tolerance. 20
A.2.5 Input return loss . 21
A.2.6 Output return loss. 22
A.2.7 Input and output jitter . 23
A.2.8 Frame structure . 24
A.2.9 Frame alignment procedure . 25
Annex B (normative): Definition of CMI code .27
B.1 General.27
B.2 Definition .27
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4 ETSI EN 300 690 V1.2.1 (2001-07)
Annex C (normative): Definition of frame structure.28
C.1 Frame structure at 139 364 kbit/s .28
C.1.1 Trail access point identifier format. 29
C.1.1.1 CRC-7 calculation - multiplication and division process . 30
C.1.1.2 CRC-7 calculation - encoding procedure . 30
C.1.1.3 CRC-7 calculation - decoding procedure . 30
Annex D (normative): Requirements Table (RT).31
Annex E (informative): Bibliography.32
History .33
ETSI
5 ETSI EN 300 690 V1.2.1 (2001-07)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://www.etsi.org/ipr).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Access and
Terminals (AT).
The present document resulted from a mandate from the Commission of the European Community (CEC) to provide
standards for the support of the Directive on Open Network Provision (ONP) of leased lines (92/44/EEC).
There are two other standards directly related to the present document:
- EN 300 686: "Access and Terminals (AT); 34 Mbit/s and 140 Mbit/s digital leased lines (D34U, D34S, D140U,
D140S); Network interface presentation";
- EN 300 688: "Access and Terminals (AT); 140 Mbit/s digital leased lines (D140U and D140S); Connection
characteristics".
The present document is based on information from ITU-T Recommendations and ETSI publications and the relevant
documents are quoted where appropriate.
National transposition dates
Date of adoption of this EN: 29 June 2001
Date of latest announcement of this EN (doa): 30 September 2001
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 March 2002
Date of withdrawal of any conflicting National Standard (dow): 31 March 2002
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6 ETSI EN 300 690 V1.2.1 (2001-07)
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 of a minimum set of leased lines with harmonized technical characteristics.
The 140 Mbit/s unstructured and structured leased lines are not part of the minimum set of leased lines under the leased
line Directive, however these standards are being written with the intention that where 140 Mbit/s leased lines are
offered, they will be in accordance with these standards.
Two categories (voluntary and regulatory) of standard were used for the interfaces of terminal equipment designed for
connection to the ONP leased lines. Technical Basis for Regulations (TBRs) gave the earlier essential requirements
under the Directive 91/263/EEC, later replaced by 98/13/EC, for attachment to the leased lines, whereas other voluntary
standards (ETSs or ENs) gave the full technical specifications for these interfaces. The present document, which is
based on an earlier ETS, belongs to the second category.
The requirements of TBR 25 are a subset of the present document.
The present version of the present document has been produced to introduce some necessary changes.
ETS 300 166 and ITU-T Recommendation G.703 [4] were used as the basis for the terminal equipment interface aspects
of the present document.
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7 ETSI EN 300 690 V1.2.1 (2001-07)
1 Scope
The present document specifies the mechanical and electrical characteristics (except safety, overvoltage and EMC
aspects), the necessary functional characteristics and the corresponding conformance tests for a terminal equipment
interface for:
- connection to the network termination points of 139 264 kbit/s digital unstructured leased lines (D140U); and
- connection to the network termination points of 139 264 kbit/s digital structured leased lines (D140S) which
support an unstructured 138 240 kbit/s information transfer rate.
These leased lines are defined in EN 300 686 and EN 300 688.
The present document is written only to ensure that the interface of the terminal equipment is compatible with the
140 Mbit/s digital unstructured or structured leased lines. The present document is applicable to all interfaces designed
for connection to the leased line, however in the cases of apparatus that carries a particular service, of complex
apparatus and of apparatus in private networks, other requirements may apply in addition to the present document.
Customer premises wiring and installation between the terminal equipment and the Network Termination Point (NTP)
are outside the scope of the present document.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
[1] IEC 60169-8 (1978): "Radio-frequency connectors. Part 8: R.F. coaxial connectors with inner
diameter of outer conductor 6,5 mm (0,256 in) with bayonet lock - Characteristic impedance
50 ohms (Type BNC)".
[2] IEC 60169-13 (1976): "Radio-frequency connectors. Part 13: R.F. coaxial connectors with inner
diameter of outer conductor 5,6 mm (0,22 in) - Characteristic impedance 75 ohms (Type 1,6/5,6) -
Characteristic impedance 50 ohms (Type 1,8/5,6) with similar mating dimensions".
[3] ISO/IEC 10173 (1998): "Information technology - Telecommunications and information exchange
between systems - Interface connector and contact assignments for ISDN primary rate access
connector located at reference points S and T".
[4] ITU-T Recommendation G.703 (1998): "Physical/electrical characteristics of hierarchical digital
interfaces".
[5] ITU-T Recommendation O.151 (1992): "Error performance measuring equipment operating at the
primary rate and above".
[6] ITU-T Recommendation O.171 (1997): "Timing jitter and wander measuring equipment for digital
systems which are based on the plesiochronous digital hierarchy (PDH)".
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8 ETSI EN 300 690 V1.2.1 (2001-07)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
frame: repetitive set of consecutive bits in which the position of each bit can be identified by reference to a frame
alignment signal
frame alignment signal: distinctive signal inserted in every frame always occupying the same relative position within
the frame and used to establish and maintain frame alignment
leased lines: 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
PRBS(2 -1): Pseudo Random Bit Sequence (PRBS) (as defined in clause 2.2 of ITU-T Recommendation O.151)
terminal equipment: equipment intended to be connected to the public telecommunications network, i.e.:
- 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 the present document, the following abbreviations apply:
AIS Alarm indication Signal
ASCII American Standard Code for Information Interchange
ATM Asynchronous Transfer Mode
BIP-8 Bit Interleaved Parity (8 bit)
BNC Bayonet Nut Connector
CMI Coded Mark Inversion
CRC-7 Cyclic Redundancy Check (7 bit)
dc direct current
D140S 140 Mbit/s digital structured leased line
D140U 140 Mbit/s digital unstructured leased line
EM Error Monitoring
EMC ElectroMagnetic Compatibility
FA1 Frame Alignment byte 1
FA2 Frame Alignment byte 2
GC General purpose Communications channel
LOF Loss Of Frame
LOS Loss Of Signal
LSB Least Significant Bit
MA Maintenance and Adaptation
MSB Most Significant Bit
NR Network operator byte
NTP Network Termination Point
ONP Open Network Provision
ppm parts per million
PRBS Pseudo Random Bit Sequence
RDI Remote Defect Indication
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9 ETSI EN 300 690 V1.2.1 (2001-07)
REI Remote Error Indication
RT Requirements Table
RX RX is a signal input (at either the terminal equipment or the test equipment, see figure 1)
SDH Synchronous Digital Hierarchy
TM Timing Marker
TR TRail trace
TTI Trail Trace Identifier
TU Tributary Unit
TUG Tributary Unit Group
TX TX is a signal output (at either the terminal equipment or the test equipment, see figure 1)
UI Unit Interval
4 Requirements
The D140U 139 264 kbit/s unstructured leased line provides a bi-directional point-to-point digital leased line for the
support of an unstructured 139 264 kbit/s information transfer rate. Any structuring of the data is the responsibility of
the user.
The D140S 139 264 kbit/s structured leased line provides a bi-directional point-to-point digital leased line for the
support of an unstructured 138 240 kbit/s information transfer rate. Any structuring of the data within the transparent
138 240 kbit/s part of the frame is the responsibility of the user.
For both D140U and D140S the provision of timing is the responsibility of the user; however, in certain installations the
leased line provider may be able to offer a leased line that is synchronized to the network.
4.1 Mechanical characteristics
The terminal equipment shall provide at least one of the methods of connection given in clauses 4.1.1 and 4.1.2.
NOTE 1: When connecting the terminal equipment to the NTP, any difference in ground potential between the two
equipments may produce a voltage across the signal ground connection and may cause damage. See
EN 50310 for details of earthing requirements within the customer's premises.
NOTE 2: The transmit pair is the output from the terminal equipment interface. The receive pair is the input to the
terminal equipment interface, as shown in figure 1. Where the terms "output" and "input" are used
without qualification in the present document, they refer to the terminal equipment interface.
NOTE 3: Normal practice is for the outer conductors of the input and output connectors to be connected via a dc
path to the signal ground and thence to ground. This connection is to reduce EMC emissions. If there is a
difference in ground potential between the terminal equipment and the NTP, this arrangement may result
in high currents in the outer conductors and cause damage.
To prevent this problem, dc isolation may be introduced between the terminal equipment and the NTP,
for example by introducing dc isolation between the outer conductor and the signal ground in the terminal
equipment. Careful attention should be given to the requirements of standards on installation earthing
practice.
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10 ETSI EN 300 690 V1.2.1 (2001-07)
OUTPUT INPUT
TX RX
TERMINAL
NETWORK
EQUIPMENT
INTERFACE
INTERFACE
RX TX
INPUT OUTPUT
Figure 1
4.1.1 Sockets
Requirement: The terminal equipment interface shall provide two coaxial 75 Ω sockets, one each for transmit and
receive; these sockets being either:
a) 75 Ω sockets (type 1,6/5,6) complying with IEC 60169-13 [2]; or
b) 75 Ω BNC sockets complying with the general requirements of IEC 60169-8 [1] with the mating dimensions
specified in annex B of ISO/IEC 10173 [3].
The outer conductor of the coaxial pair shall be connected to signal ground both at the input port and at the output port.
Test: There shall be a visual inspection that the sockets are of the correct type.
4.1.2 Plugs
Requirement: The terminal equipment interface shall provide two coaxial 75 Ω plugs at the end of a cord (or cords),
one each for transmit and receive; these plugs being either:
a) 75 Ω plugs (type 1,6/5,6) complying with IEC 60169-13 [2]; or
b) 75 Ω BNC plugs complying with the general requirements of IEC 60169-8 [1] with the mating dimensions
specified in annex B of ISO/IEC 10173 [3].
The outer conductor of the coaxial pair shall be connected to signal ground both at the input port and at the output port.
NOTE: There is no requirement on the method of connection of the cord (or cords) to the terminal equipment.
Test: There shall be a visual inspection that the plugs are of the correct type.
4.2 Electrical characteristics
4.2.1 Output port
4.2.1.1 Signal coding
Requirement: The signal transmitted at the output port shall comply with the Coded Mark Inversion (CMI) encoding
rules (see annex B).
Test: The test shall be conducted according to clause A.2.1.
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11 ETSI EN 300 690 V1.2.1 (2001-07)
4.2.1.2 Waveform shape
Requirement: The pulse at the output port shall comply with the requirements given in figures 2 and 3 and table 1;
based on ITU-T Recommendation G.703 [4].
Table 1: Waveform shape at output port
Pulse shape Nominally rectangular and conforming with the masks shown in
figures 2 and 3
Test load impedance
75 Ω non-reactive
Peak to peak voltage 1,0 ± 0,1 V
Rise time between 10 % and 90 % ≤ 2ns
amplitudes of the measured steady state
amplitude
Transition timing tolerance (referred to the Negative transitions: ±0,1 ns
mean value of the 50 % amplitude points Positive transitions at unit interval boundaries: ±0,5 ns
of the negative transition) Positive transitions at mid-interval: ±0,35 ns
NOTE 1: The maximum "steady state" amplitude shall not exceed the 0,55 V limit. Overshoots and other transients
are permitted to fall into the dotted area, bounded by the amplitude levels 0,55 V and 0,60 V, provided they
do not exceed the steady state level by more than 0,05 V.
NOTE 2: The rise time and decay time shall be measured between -0,4 V and 0,4 V and shall not exceed 2 ns.
Figure 2: Mask of a pulse corresponding to a binary 0
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12 ETSI EN 300 690 V1.2.1 (2001-07)
T = 7,18 ns
V
0,60
(see note 1) (see note 1)
0,55
0,50
1ns
0,45
1ns
0,40
0,1 ns 0,1 ns
0,5 ns 0,5 ns
Nominal 0,05
zero level
-0,05
3,59 ns 3,59 ns
1,35 ns 1,35 ns
1ns 1ns
-0,40
1,795 ns 1,795 ns
-0,45
-0,50
(see note 1)
-0,55
-0,60
Negative
Positive
transition
transition
NOTE 1: The maximum "steady state" amplitude shall not exceed the 0,55 V limit. Overshoots and other transients
are permitted to fall into the dotted area, bounded by the amplitude levels 0,55 V and 0,60 V, provided they
do not exceed the steady state level by more than 0,05 V.
NOTE 2: The inverse pulse shall have the same characteristics, noting that the timing tolerance at the level of the
negative and positive transitions are ±0,1 ns and ±0,5 ns respectively.
NOTE 3: The rise time and decay time shall be measured between -0,4 V and 0,4 V and shall not exceed 2 ns.
Figure 3: Mask of a pulse corresponding to a binary 1
Test: The test shall be conducted according to clause A.2.2.
4.2.1.3 Output timing
The terminal equipment may derive its timing from:
a) an internal source (e.g. an internal clock);
b) an external reference signal input;
c) the received signal at the input port.
Requirement: For each of the timing arrangements intended for use, the bit rate at the output port shall be within the
limits of 139 264 kbit/s ± 15 parts per million (ppm), when any relevant external signal, including the received signal at
the input port, is within its stated tolerance.
NOTE: The tolerance of ±15 ppm relates to the transmission capability of the leased line. Tighter limits may be
needed to ensure satisfactory end to end interworking with the distant terminal equipment.
Test: The test shall be conducted according to clause A.2.3.
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13 ETSI EN 300 690 V1.2.1 (2001-07)
4.2.1.4 Output return loss
Requirement: The output return loss at the terminal equipment interface, with respect to 75 Ω, shall be greater than or
equal to the values given in table 2, which is taken from clause 12.2 of ITU-T Recommendation G.703 [4].
Table 2: Output port minimum return loss
Frequency range Return loss
7MHzto210MHz 15dB
Test: The test shall be conducted according to clause A.2.6.
4.2.1.5 Output jitter
Requirement: The peak-to-peak output jitter shall not exceed the limits of table 3 when measured with a bandpass
filter with linear cut-off with the defined cut-off frequencies. At frequencies below the lower 3 dB point, the attenuation
of the high pass filter shall rise with a value greater than, or equal to, 20 dB per decade. At frequencies above the upper
3 dB point, the attenuation of the low pass filtration shall rise with a value greater than, or equal to, 60 dB per decade.
For the purpose of testing, any signal input from which the output timing is derived shall be provided with the
maximum tolerable input jitter, and with the maximum tolerable input frequency deviation, as specified by the
manufacturer.
Where the output timing of the terminal equipment is taken from the leased line, the input to the terminal equipment
shall be provided with components of sinusoidal jitter at points on the curve of figure 4 and table 5.
Table 3: Maximum output jitter
Measurement filter bandwidth Output jitter
Lower cut-off (high pass) Upper cut-off (low pass) Unit Interval (UI)
peak-to-peak (maximum)
200 Hz 3 500 kHz 0,4
10 kHz 3 500 kHz 0,075
Test: The test shall be conducted according to clause A.2.7.
4.2.1.6 Output frame structure
The requirement of this clause applies to terminal equipment for connection to the D140S leased line. For terminal
equipments for connection to the D140U leased line, there is no requirement on the structure of the output bit stream.
Requirement: For terminal equipments for connection to the D140S leased line, the bit stream transmitted at the output
of the terminal equipment shall be structured as defined in annex C.
Bit 1 of byte Maintenance and Adaptation (MA), a Remote Defect Indication (RDI), shall be set to "1" within 250 μsof
the detection of loss of received frame alignment (see clause 4.2.2.7), and set to "0" within 250 μs on gaining frame
alignment.
Test: The test shall be conducted according to clauses A.2.8 and A.2.9.
4.2.2 Input port
4.2.2.1 Signal coding
Requirement: The input port shall decode without error CMI encoded signals in accordance with CMI encoding
rules (see annex B).
Test: The test shall be conducted according to clause A.2.4.
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14 ETSI EN 300 690 V1.2.1 (2001-07)
4.2.2.2 Input return loss
Requirement: The input return loss with respect to 75 Ω at the interface shall be greater than or equal to the values
given in table 4, which is taken from clause 12.3 of ITU-T Recommendation G.703 [4].
Table 4: Input port minimum return loss
Frequency range Return loss
7MHzto210MHz 15dB
Test: The test shall be conducted according to clause A.2.5.
4.2.2.3 Input loss tolerance
Requirement: The input port shall decode without errors a 139 264 kbit/s signal as defined in clauses 4.2.1.1 and
4.2.1.2 above but modified by a cable or artificial cable with the following characteristics:
a) attenuation that follows a √f law with values throughout the range 0 dB to 12 dB at 70 MHz; and
b) characteristic impedance of 75 Ω with a tolerance of ±20 % over the frequency range from 7 MHz to 210 MHz.
Test: The test shall be conducted according to clause A.2.4.
4.2.2.4 Input jitter tolerance
Requirement: The terminal equipment shall tolerate at its input port the maximum input jitter as shown in figure 4 and
table 5 (taken from ITU-T Recommendation G.823).
NOTE: Terminal equipment with more than one input will normally need to be designed with a wander buffer of
at least 18 microseconds, however, to accommodate the wander that may be produced by Synchronous
Digital Hierarchy (SDH) networks, up to 40 microseconds may be needed.
peak-to-peak jitter
A1
A2
f1 f2 f3 f4
jitter frequency
Figure 4: Input jitter tolerance
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15 ETSI EN 300 690 V1.2.1 (2001-07)
Table 5: Input jitter tolerance
Peak-to-peak amplitude (UI) Frequency
A1 A2 f1 f2 f3 f4
1,5 0,075 200 Hz 500 Hz 10 kHz 3 500 kHz
Test: The test shall be conducted according to clause A.2.7.
4.2.2.5 Input clock tolerance
Requirement: The terminal equipment shall decode without error CMI encoded signals, as defined in annex B, for all
bit rates within the limits of 139 264 kbit/s ± 15 ppm.
Test: The test shall be conducted according to clause A.2.7.
4.2.2.6 Input frame structure
The requirement of this clause applies to terminal equipment for connection to the D140S leased line. For terminal
equipments for connection to the D140U leased line, there is no requirement on the structure of the input bit stream.
Requirement: The input port shall accept an input bit stream with a frame structure as defined in annex C. The terminal
equipment shall be capable of achieving frame alignment, as detailed in clause 4.2.2.7, in order to separate the user data
from the frame information.
Test: The test shall be conducted according to clause A.2.4.
4.2.2.7 Frame alignment procedure
The requirement of this clause applies to terminal equipment for connection to the D140S leased line. For terminal
equipments for connection to the D140U leased line, there is no requirement on the frame alignment procedure.
Requirement: The terminal equipment shall perform a frame alignment procedure on the 139 264 kbit/s signal in order
to gain or to recover frame alignment. To obtain frame alignment, the terminal equipment shall search for the FA1and
FA2 bytes contained within the received bit stream. Frame alignment shall be continuously checked with the presumed
frame start position for the correct frame alignment.
Frame alignment shall be considered to have been obtained, or recovered, when three consecutive non-errored frame
alignment signals (FA1 and FA2) have been found.
Frame alignment shall be considered to have been lost when either:
a) four consecutive frame alignment signals (FA1 and FA2) are detected in error (i.e. ≥1error in each FA1and
FA2); or
b) 986 or more frames with one or more BIP-8 violations are detected in a block of 1 000 frames.
When frame alignment is achieved, even bit parity (BIP-8) shall be computed by the terminal equipment for each bit n
of every byte of the preceding frame and compared with bit n of the EM byte recovered from the current frame. A
difference between the computed BIP-8 and the EM value shall be taken as evidence of one or more errors in the
previous frame.
Should a research for frame alignment be initiated for any reason, then the new search for frame alignment should start
1 bit displaced forward from the position of the last indication of frame alignment.
NOTE: The above is recommended in order to avoid repeated alignment on to a simulation of the framing
location.
Test: The test shall be conducted according to clause A.2.9.
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16 ETSI EN 300 690 V1.2.1 (2001-07)
4.3 Safety
Requirements for safety are outside the scope of the present document.
Safety standards are published by CENELEC.
NOTE 1: An example of such a CENELEC product safety standard is EN 60950 (see annex E).
NOTE 2: For safety categories of interfaces, see EG 201 212. This document is also available from CENELEC as
ROBT-002.
4.4 Overvoltage
Overvoltage aspects are outside of the scope of the present document.
4.5 ElectroMagnetic Compatibility (EMC)
EMC requirements are outside the scope the present document.
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17 ETSI EN 300 690 V1.2.1 (2001-07)
Annex A (normative):
Test methods
A.1 General
This annex describes the test principles to determine the compliance of a terminal equipment against the requirements
of the present document.
It is outside the scope of this annex to identify the specific details of the implementation of the tests.
A terminal equipment may be designed for through-connecting and may fulfil the electrical requirements only if
through-connected. In these cases the requirements of the present document are valid and the tests shall be carried out
with the through-connection terminated as specified by the manufacturer.
Details of test equipment accuracy and the specification tolerance of the test devices are not included in all cases.
Where such details are provided they shall be complied with, but the way they are expressed shall not constrain the
method of implementing the test.
NOTE: Attention is drawn to the issue of measurement uncertainty which may be addressed in future documents.
Not all the required test results make allowance for spurious events during testing (e.g. errors due to EMC
effects), which may make it necessary to repeat a test.
The test configurations given do not imply a specific realization of test equipment or test arrangement, or the use of
specific test devices for conformance testing. However, any test configuration used shall provide those test conditions
specified under "interface state", "stimulus" and "monitor" for each individual test.
The test equipment shall be a device, or a group of devices, that is capable of generating a stimulus signal conforming to
the present document and capable of monitoring the signal received from the interface.
A.1.1 Additional information to support the test
The following facilities shall be provided by the terminal equipment interface under test:
a) an ability to configure the terminal equipment such that it provides a transparent loopback of the data contained
within the payload at the input to the output; and
b) an ability to transmit a given bit pattern, e.g. PRBS(2 -1), within the payload; or -1
c) where a or b cannot be provided, an alternative means of performing the test.
NOTE: Where the terminal equipment is for connection to the D140S leased line, the REI bit may be used as an
alternative to a transparent loopback in order to determine if data at the input has been correctly received.
A.1.2 Equipment connection
The tests shall be applied at the sockets or plugs defined in clauses 4.1.1 and 4.1.2. Connecting cable between the
sockets and test equipment shall be kept to a minimum, except where cable is specified as part of the test.
Where plugs are provided at the end of a cord as defined in clause 4.1.2, the tests specified in clauses A.2.2, A.2.5 and
A.2.6 may be performed at the point of connection of the cord to the terminal equipment, since the requirements are
based on ITU-T Recommendation G.703 [4] which makes no allowance for any plug and cord.
ETSI
18 ETSI EN 300 690 V1.2.1 (2001-07)
A.2 Test methods
One test may cover more than one requirement. The scope of each test is defined under the heading "purpose".
A.2.1 Signal coding at the output port
Purpose: To verify that the signal coding at the terminal equipment output port complies with the CMI
coding rules as required by clause 4.2.1.1.
Test configuration: Figure A.1.
TX RX
TER M IN AL TES T
EQ U IPM ENT EQ U IPM ENT
RX TX
Figure A.1: Signal coding at output port
Interface state: Powered.
Stimulus: The terminal equipment shall transmit a pseudo random bit stream, e.g. PRBS(2 -1). For
terminal equipment which can generate a structured signal in accordance with annex C, the
PRBS may be transmitted in the payload section of the frame. For terminal equipment which
cannot generate such a structured signal, the PRBS should be transmitted in the whole bit
stream.
Monitor: The output bit stream for a test period of sufficient time to allow transmission of
100 occurrences of the above patterns plus the latency period of the error detection mechanism.
Results: There shall be no errors in the CMI encoding.
A.2.2 Waveform shape at the output port
Purpose: To verify conformance of the output waveform shape with the requirements of clause 4.2.1.2.
RX
TX
TERMINAL MEASURING
EQUIPMENT EQUIPMENT
75 ohms
±0,25 %
RX
Figure A.2: Waveform shape at output port
ETSI
19 ETSI EN 300 690 V1.2.1 (2001-07)
Test configuration: Figure A.2.
Interface state: Powered.
Stimulus: Undefined.
Monitor: Marks and spaces transmitted from the terminal equipment, measuring the amplitude and pulse
shapes corresponding to binary 0 and binary 1. A bandwidth of 1 GHz or greater shall be used
to ensure the capture of over or undershoot of the pulse.
The overall measurement accuracy shall be better than 30 mV. For all measurements using
these masks, the signal shall be ac coupled, using a capacitor of not less than 0,01µF, to the
input of the oscilloscope (or other equipment) used for the measurement. The nominal zero for
both masks shall be aligned with the oscilloscope trace with no input signal. With the signal
then applied, the vertical position of the trace can then be adjusted with the objective of
meeting the limits of the masks. Any such adjustment shall be the same for both masks and
shall not exceed ±0,05 V. This shall be checked by removing the input signal again and
ensuring that the trace lies within ±0,05 V of the nominal zero level of the masks.
The masks allow for high frequency jitter caused by intersymbol interference in the output
stage, but not for jitter present in the timing signal associated with the source of the interface
signal.
When using an oscilloscope technique to determine pulse compliance with the mask, it is
important that successive traces of the pulses overlay in order to suppress the effects of low
frequency jitter. This can be accomplished by several techniques, e.g.:
a) triggering the oscilloscope on the measured waveform; or
b) providing both the oscilloscope and the pulse output circuits with the same clock signal.
Results: Each pulse in a coded pulse sequence shall meet the limits of the relevant mask given in
figures 2 and 3, irrespective of the state of the preceding or succeeding pulses, with both pulse
masks fixed in the same relation to a common timing reference, i.e. with their normal start and
finish edges coincident.
The rise and decay time shall be measured between -0,4 V and 0,4 V and shall not exceed 2 ns.
A.2.3 Output timing
Purpose: To measure the output timing as defined in clause 4.2.1.3.
Test configuration: Figure A.3.
RX
TX
TERMINAL MEASURING
EQUIPMENT EQUIPMENT
External
TX
RX
reference
signal input
SEPARATE
CLOCK
TIMING
GENERATOR
SOURCE
(if required)
Figure A.3: Output timing
ETSI
20 ETSI EN 300 690 V1.2.1 (2001-07)
Interface state: Powered.
Stimulus: The terminal equipment shall be configured to provide output timing from each of its intended
timing arrangements. Any external reference signal input, including the input port, from which
timing can be derived, shall be provided with timing at the bit rate limits as specified by the
terminal equipment manufacturer.
Monitor: The bit rate of the signal decoded from output port of the terminal equipment.
Results: The bit rate shall be within the limits given in clause 4.2.1.3.
A.2.4 Input signal coding and loss tolerance
Purpose: To verify the input port signal coding (clause 4.2.2.1) both without cable (i.e. 0 dB attenuation
loss) and with a cable attenuation of 12 dB (clause 4.2.2.3).
Test configuration: Figure A.4.
TX
RX
TERMINAL TEST
EQUIPMENT EQUIPMENT
CABLE
SIMULATOR
TX
RX
Figure A.4: Input coding and loss tolerance
The cable simulator shall have an attenuation of 12 dB measured at 70 MHz and an attenuation
characteristic that follows a √f law over the frequency range 7 MHz to 210 MHz.
The conformance of the interface shall be verified in the following test conditions:
a) without cable simulator; and
b) with cable simulator.
Interface state: Powered, with received data looped back to the output port.
Stimulus: The output signal of the test equipment shall be CMI encoded and conform to a pulse shape as
defined in figures 18 and 19 of ITU-T Recommendation G.703 [4], which are reproduced in
figures 2 and 3 of the present document. For terminal equipment which can generate a
structured signal in accordance with annex C, the bit stream shall be structured into frames
according to annex C. The binary content of t
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