ETSI ETS 300 324-1/A1 ed.1 (1996-01)
V interfaces at the digital Local Exchange (LE); V5.1 interface for the support of Access Network (AN); Part 1: V5.1 interface specification
V interfaces at the digital Local Exchange (LE); V5.1 interface for the support of Access Network (AN); Part 1: V5.1 interface specification
RE/SPS-03028
Signalizacijski protokoli in komutacija (SPS) - Vmesniki "V" pri digitalnih krajevnih centralah (LE) - Vmesnik V5.1 za podporo dostopovnega omrežja (AN) - 1. del: Specifikacija vmesnika V5.1
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST ETS 300 324-1:1997/A1:1997
01-november-1997
Signalizacijski protokoli in komutacija (SPS) - Vmesniki "V" pri digitalnih krajevnih
centralah (LE) - Vmesnik V5.1 za podporo dostopovnega omrežja (AN) - 1. del:
Specifikacija vmesnika V5.1
Signalling Protocols and Switching (SPS) - V interfaces at the digital Local Exchange
(LE); V5.1 interface for the support of Access Network (AN); Part 1: V5.1 interface
specification
Ta slovenski standard je istoveten z: ETS 300 324-1/A1 Edition 1
ICS:
33.040.30 Komutacijski in signalizacijski Switching and signalling
sistem systems
SIST ETS 300 324-1:1997/A1:1997 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ETS 300 324-1:1997/A1:1997
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SIST ETS 300 324-1:1997/A1:1997
ETS 300 324-1
AMENDMENT A1
January 1996
Source: ETSI TC-SPS Reference: RE/SPS-03028
ICS: 33.020, 33.080
V interface, V5 interface, LE, AN
Key words:
This amendment A1 modifies
the European Telecommunication Standard ETS 300 324-1 (1994)
Signalling Protocols and Switching (SPS);
V interfaces at the digital Local Exchange (LE);
V5.1 interface for the support of Access Network (AN);
Part 1: V5.1 interface specification
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16
*
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 1996. All rights reserved.
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ETS 300 324-1: February 1994/A1: January 1996
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 300 324-1: February 1994/A1: January 1996
Foreword
This amendment to ETS 300 324-1 (1994) has been produced by the Signalling Protocols and Switching
(SPS) Technical Committee of the European Telecommunications Standards Institute (ETSI).
This amendment contains changes of clauses, subclauses and annexes of ETS 300 324-1 (1994) as
detailed below:
Clauses 4 and 5: The general reference to other ETSs and ITU-T Recommendations concerning
the physical/electrical and functional characteristics of the interface layer 1 have
to be extended by specifying particular requirements for those aspects having
conceptual implications to the V5.1 interface specification.
Subclause 8.7.3: This subclause uses the term "operational and activated" as state description.
But this state name does not exist.
Amendment: The correct state name is used.
Subclause 10.4.5.5.2: This subclause refers to "different unnumbered commands". Since the only
unnumbered command which may be used for the peer-to-peer procedures of
the data link sublayer, is the SABME command, this term is not applicable.
Subclause 11.1: Editorial error: HDSL has to be replaced by HDLC.
Subclause 13.4.6.3: Table 20 (coding of PSTN FSM state) does not specify the meaning of unused
code points.
Amendment: The usage of all possible code points is clarified.
Subclause 13.4.7.5: Editorial error: The last sentence of this subclause belongs to figure 24.
Subclause 13.4.7.6: Editorial error: The last sentence of this subclause belongs to figure 25.
Subclause 13.5.2.1: This subclause mentions the code point of the described protocol error cause
value (Protocol discriminator error). The other subclauses which describe the
error handling procedure do not.
Amendment: Delete the mentioning of the code point in subclause 13.5.2.1.
Subclause 13.5.2.10: This subclause has been specified as requiring the generation of two error
indications for one received unexpected event.
If the LE PSTN protocol receives an unexpected event, it shall generate an error
indication and send a STATUS ENQUIRY message.
On receipt of a STATUS message with incompatible path states, the LE shall
generate again an error indication.
Amendment: The requirement for generating two error indications at the LE side
is deleted.
The used term "message sequence error" is ambiguous.
Amendment: Delete the term "message sequence error".
Subclause 13.5.3: The used term "message sequence error" is ambiguous.
Amendment: Replace the term "message sequence error" by "unexpected
message".
Subclause 13.5.3.1.1.2: Editorial error: This subclause contains a wrong subclause reference.
Subclause 13.7: The PSTN state tables concerning the handling of unexpected events in state
AN7 are contradictory to subclause 13.5.3.5.1.2 which reflects the basic
intention that in state AN7 no reaction on messages other than DISCONNECT
and DISCONNECT COMPLETE is to be required, because the PSTN protocol
FSMs are in the clearing down phase and the FSMs will be reset.
But: Table 29 requires that on receipt of PROTOCOL PARAMETER in state
AN7 the sending of a STATUS message is required.
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Amendment: Table 29, state AN7, event PROTOCOL PARAMETER: No
STATUS has to be sent. The text in subclause 13.5.4.1.2 and the SDL diagram
in figure L.9.10 are adapted accordingly.
The PSTN state tables create error indications by itself in the case of port
blocking or PSTN restart.
If a DISCONNECT COMPLETE message is received in the Port Blocked
(AN6/LE6) or Out of Service (AN0/LE0) state of the PSTN protocol, the
STATUS/STATUS ENQUIRY procedure will be invoked. As a result, the LE
receives a STATUS message. According to table 30, the LE PSTN protocol has
then to generate an internal error indication to the LE-system management
(table 30: STATUS received in LE0/LE6).
But: Upon receipt of MDU-CTRL (port blocked) or MDU-CTRL (restart request),
the PSTN protocol has to send a DISCONNECT COMPLETE message before
entering the proper state. This applies to both sides. Therefore, it is most likely
that one side will receive this message in the Port Blocked or Out of Service
state (the port blocking and restart procedure are synchronized by the Control
protocol).
Amendment: The handling of STATUS in table 30 is changed.
LE PSTN state table does not cover call collision in the Line Information state.
Amendment: Allow the sending of DISCONNECT COMPLETE in state LE2.
Editorial: Note 3 refers to the SDL diagrams. Since the SDL diagrams are only
informative, this is an inappropriate reference. As note 3 is not urgently needed
to understand the table, it is deleted.
Subclause 14.1.3.4: Assume a state mismatch of the AN and LE ISDN user port FSMs, such that the
AN stays in AN2.2 (access activated) and LE enters LE1.0 (blocked).
If the LE then tries to unblock and synchronize the port by sending FE201,
according to table 35 the AN will not send any message over the V5.1 interface
and the LE FSM hangs up in state LE1.1 (local unblock).
Amendment: AN sends the response FE104 back to LE.
Subclause 14.4.1.3: Note 3 of table 48 is contradictory to table 55. Note 3 of table 48 implies that the
variant information element is included in a common control message for the
control-function-IDs "blocking started", "restart request" and "restart complete".
This is not correct (refer to table 55). Furthermore the information given in the
notes of table 48 is redundant.
Amendment: Replace notes 1 to 3 of table 48 by a general note referring to
table 55.
Subclause 14.4.4.1: The fifth paragraph of this subclause uses a wrong state name.
Amendment: The state name is corrected.
Subclause 14.4.4.2.10: Editorial error: This subclause contains wrong table references.
Annex C, item 2): Editorial error: This item contains wrong subclause references.
Annex C, item 5): According to annex C, item 5), the receiving entity of an unblock request
message is allowed to send no response back because it does not agree with
the unblock request. But then it is not possible for the sender of the unblock
request to distinguish between such a disagreement and a mismatch of the port
FSMs which has to be resolved by a block-unblock sequence.
Amendment: To avoid a situation where the FSMs stay misaligned and
undetected, the receiver of a MPH-UBR shall respond to an unblock request
within a certain time limit.
Annex C, item 12): The text concerning re-provisioning verification is clarified.
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Annex C, item 13): Initial state of the ISDN user port FSM, PSTN user port FSM and PSTN protocol
after system start up is not defined clearly.
Amendment: The system startup procedure is clarified. The SDL diagrams in
figures L.9.1, L9.9, L25.1, L25.7 are adapted accordingly.
It is stated that the interface and the variant ID shall be checked during system
startup. No procedure exists for the case of an unsuccessful check.
Amendment: The treatment of a unsuccessful system startup is be the same as
in the case of an unsuccessful restart (refer to annex C, item 14 b), last
paragraph).
Annex C, item 14): This item defines an asymmetrical PSTN restart procedure (master-slave
relationship). This leads to a lock-up situation if the restart is required from both
sides at the same point in time.
Amendment: The restart procedure is defined in a symmetrical way. The SDL
diagrams in figures L.9.17.4, L17.8, L33.4, L33.8 are adapted accordingly.
Annex C, item 17): If TC3 expires only on one side of the V5.1 interface, a mismatch of the PSTN
protocol FSMs after a re-establishment of the PSTN_DL can persist.
Amendment: The PSTN restart procedure is added in case of a re-
establishment of the PSTN_DL.
Annex C, table C.1: "Cause for start" of Timer TC2 is wrong.
Amendment: The cause for start is corrected.
Annex L, figure L.9.5: Figure L.9.5 is contradictory to table 29 concerning the handling of an
ESTABLISH message in state AN4. Table 29 requires "No action, no state
change", figure L.9.5 requires the sending of a STATUS message.
Amendment: Update of figure L.9.5 according to table 29.
Annex L, figure L.17.1: If during startup the CONTROL_DL is not able to establish the connection
(sending of SABME four times), it sends MDL-RELEASE-INDICATION to
system management. In figure L17.1, this event is not shown and the required
reaction of system management is not clear.
Amendment: Update of figure L.17.1 to show the sending of MDL-RELEASE-
INDICATION.
Annex L, figure L.17.2: Figure L.17.2 is contradictory to annex C, item 13), which requires that the
variant and interface ID shall be checked during system startup. Figure L.17.2
shows only a check of the interface ID.
Amendment: Update of figure L.17.2 by adding a decision for the correct variant.
The treatment of MDU-CTRL(request variant&interface ID) is missing in states
AN1/LE1(SYS).
Amendment: Take into account MDU-CTRL(request variant&interface ID) from
AN/LE Control protocol.
The handling of DL release is missing in states AN2/LE2(SYS) (Activate PSTN).
Amendment: Take into account MDL-RELEASE-INDICATION from AN/LE
PSTN_DL.
Annex L, figure L.17.7: The recovery from PSTN_DL release is not working properly.
When MDL-RELEASE-INDICATION is received, timer TC3 is started and
MDL-ESTABLISH-REQUEST is sent to PSTN_DL. When PSTN_DL receives
MDL-ESTABLISH-REQUEST it sends a SABME command over the V5.1
interface. IF PSTN_DL receives no response, it repeats the SABME three times
having breaks of 1 second between each transmission. If PSTN_DL does not
receive any response from the remote side after up to 4 seconds it will send
again MDL-RELEASE-INDICATION to system management, which then starts
TC3 again and returns MDL-ESTABLISH-REQUEST to PSTN_DL.
Amendment: TC3 is fixed to 15 seconds, and thus it will never time out.
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When PSTN_DL finally manages to re-establish the connection and returns
MDL-ESTABLISH-CONFIRMATION to system management, the condition "TC3
running" is insufficient to determine the status of the PSTN ports (blocked or
unblocked). Assume that TC3 could time out. The PSTN ports will then be
blocked. If MDL-RELEASE-INDICATION is however once more received, TC3
is restarted. Then if MDL-ESTABLISH-CONFIRMATION is received TC3 is
running but the port unblock procedure would need to be initiated.
Amendment: Update of figure L.17.7 to avoid deadlocks.
Annex L, Figure L25.3: The handling of a call collision in the Line information case is not covered.
Amendment: Show treatment of FE-disconnect_complete_request in state LE2.
Annex L, figure L.27.1: Editorial error: The input symbol for PORT CONTROL ACK needs to be flipped.
Annex L, figure L.27.2: Editorial error: Timer TO1 is misspelled.
Annex L, figure L.33.1: Same as figure L.17.1.
Annex L, figure L.33.2: Same as figure L.17.2.
Annex L, figure L.33.5: This figure is not in line with annex C, item 12). MDU-CTRL (blocking started) is
missing.
Amendment: Update of figure L.33.5 to include MDU-CTRL (blocking started).
Annex L, figure L.33.7: Same as figure L.17.7.
Transposition dates
Date of adoption of this amendment: 12 January 1996
Date of latest announcement of this amendment (doa): 30 April 1996
Date of latest publication or endorsement of this amendment (dop/e): 31 October 1996
Date of withdrawal of any conflicting National Standard (dow): 31 October 1996
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Amendments
Page 16, clause 2
Add the following normative references:
[8] CCITT Recommendation O.9 (1988): "Measuring arrangements to assess the
degree of unbalance about earth".
[9] CCITT Recommendation O.151 (1992): "Error performance measuring
equipment operating at the primary rate and above".
Page 21, clause 4
Replace the complete text of clause 4 by:
"The V5.1 interface consists of a single 2 048 kbit/s interface as defined in ETS 300 166 [1] and
ETS 300 167 [2].
The electrical and physical characteristics of the interface shall conform to ETS 300 166 [1], 2 048 kbit/s
case.
Two interface presentation alternatives are defined in ETS 300 166 [1], the balanced interface pair type
and the coaxial type. According to the two alternatives of interface applications shown in figure 1, it is left
to the network operator to request the interface presentation required.
interface
V5.1
AN
LE
Ia Ib
Ib
Ia
transparent
AN LE
digital link
Ia = interface point at the AN side
Ib = interface point at the LE side
Figure 1: V5.1 application with and without transparent digital link
This clause identifies the layer 1 requirements from the referenced specifications including the specific
characteristics and parameters.
The specific requirements and characteristics from ETS 300 166 [1] and CCITT Recommendation G.703
are listed in table 0a. Where the requirements do not fit into the table, only the reference is shown and the
detailed requirements are given below.
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Table 0a: Electrical/physical requirements from ETS 300 166 [1] or CCITT Recommendation G.703
Item Requirements based on ETS 300 166 or AN LE
CCITT Recommendation G.703
a) Bit rate during operational condition synchronous to LE synchronous to LE
internal clock
b) Bit rate in free running mode
≤ ±50 ppm ≤ ±50 ppm for AIS
c) Code HDB3 (annex A/G.703)
d) Pulse shape figure 15/G.703
e) Pairs in each direction no test
f) Over voltage requirement annex B/G.703
- symmetrical interface figures B-1/G.703 and B-2/G.703
- coaxial interface
g) Test load impedance
- input return loss 6.3.3/G.703
- output return loss 5.3 [1]
h) Pulse shape normalized characteristics
- nominal peak voltage of a mark
balanced 3 V
coaxial 2,37 V
- peak voltage of a space
balanced 0 ± 0,3 V
coaxial 0 ± 0,237 V
- nominal pulse width covered by item d)
i) Relative tolerance between consecutive pulses
- ratio of the amplitudes at center of pulse 0,95 to 1,05
- ratio of widths at nominal half amplitude 0,95 to 1,05
j) Maximum output jitter high-Q clock, see detailed requirements below
k) Tolerable longitudinal voltage
- symmetrical interface 5.1 [1]
- coaxial interface not applicable
l) Immunity against reflections 6.3.4/G.703
m) Output signal balance
- symmetrical interface 5.2 [1]
- coaxial interface not applicable
n) Tolerable input jitter and wander G.823 [7], table 2/G.823 (low-Q)
o) Connection of outer conductor or screen 6.4/G.703 and table 1/G.703, note 7
Detailed requirements for indicated items in table 0a:
a) The synchronization of the AN to the LE clock frequency may be through the V5.1 interface or
through a synchronization interface. The lock range of the AN shall be ≥ 1 ppm and the maximum
frequency deviation from the nominal frequency during operation shall be ≤ 1 ppm.
c) The HDB3 code is a modified Alternate Mark Inversion (AMI) code. Binary ONE bits are generally
represented by alternate positive and negative pulses, and binary ZERO bits as spaces.
Exceptions, as defined for the HDB3 code below, are made when strings of successive ZERO bits
occur in the binary signal.
In the definition below, B represents an inserted pulse conforming to the AMI rule and V represents
an AMI violation. The encoding of the binary signal in accordance with this rule includes frame
alignment bits, etc.
Each block of 4 successive ZEROs shall be replaced by 000V or B00V. The choice of 000V or
B00V shall be made so that the number of B pulses between consecutive V pulses is odd, i.e.
successive V pulses shall be of alternate polarity so that no dc component is introduced.
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d) The pulse mask given in figure 1a (which is based on figure 15/G.703) shall be met at the output
port of the layer 1 interface with the amplitude values as defined in table 0a, item h).
269 ns
(244 + 25)
20%
10%
194 ns
V=100%
(244 - 50)
10%
20%
Nominal pulse
50%
244 ns
219 ns
(244 - 25)
10% 10%
0%
10% 10%
20%
488 ns
(244 + 244)
Figure 1a: Mask of the pulse at the output port of the layer 1 interface
f) The input and output ports shall withstand without damage the following tests with 10 standard
lightning pulses (1,2/50 μs) with a maximum amplitude of U (5 negative and 5 positive impulses).
1) at the interface for symmetrical pairs:
- differential mode: with a pulse generator as defined in figure 1b (which is based on
figure B-1/G.703), no test value is specified;
- common mode: with a pulse generator as defined in figure 1c (which is based on
figure B-2/G.703), U = 100 Vdc.
25 Ohm
13 Ohm
0,03 μF
U 1 μF 76 Ohm
Figure 1b: Pulse generator 1,2/50 μμs for differential mode voltages
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a
50 Ohm
13 Ohm
b
0,03 μF 50 Ohm
U 1 μF 76 Ohm
Earth
Figure 1c: Pulse generator 1,2/50 μμs for common mode voltages at symmetrical interfaces
2) at the interface for coaxial pairs:
due to the lack of detailed requirements and test voltages there are no tests defined.
However, the pulse generator defined in figure 1b may be used for differential mode voltage
test.
g) The input port of the layer 1 interface shall meet the return loss requirements as given in table 0b.
Table 0b: Input port return loss
Frequency range (kHz) Return loss (dB)
51 to 102
≥ 12
102 to 2 048
≥
18
2 048 to 3 072
≥
14
The output port of the layer 1 interface shall meet the return loss requirements as given in table 0c.
Table 0c: Output port return loss
Frequency range (kHz) Return loss (dB)
51 to 102
≥ 6
102 to 3 072
≥
8
j) The output port of the layer 1 interface shall meet the jitter limit of ≤ 0,11 UI when measured with a
band-pass with cut-off frequencies at 40 Hz (first order linear high-pass) and 100 kHz with presence
of tolerable jitter at the relevant synchronizing input port.
k) The input port of the layer 1 interface shall meet the requirement for minimum tolerance to
longitudinal voltage and the receiver shall operate without errors with any valid input signal in the
presence of a longitudinal voltage V .
L
The test value V shall be 2 V over the frequency range 10 Hz to 30 MHz.
L rms
l) The input port of the layer 1 interface shall have adequate immunity against reflections that can
arise due to impedance irregularities at digital distribution frames and at digital output ports and
shall meet the following requirement:
A nominal aggregate signal, encoded into HDB3 and having a pulse shape as defined in the pulse
mask, shall have added to it an interfering signal with the same pulse shape as the wanted signal.
The interfering signal shall have a bit rate within the limits specified below but shall not be
synchronous with the wanted signal. The interfering signal shall be combined with the wanted signal
in a combining network, with an overall zero loss in the signal path and with the nominal impedance
75 Ω (in the case of coaxial-pair interface) or 120 Ω (in the case of symmetrical-pair interface), to
give a signal-to-interference ratio of 18 dB. The binary content of the interfering signal shall comply
15
with CCITT Recommendation O.151 [9], subclause 2.1 (2 - 1 bit period). No errors shall result
when the combined signal, attenuated by up to the maximum specified interconnecting cable loss,
is applied to the input port.
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m) The output port of the layer 1 interface shall meet the output signal balance requirement, which
shall be measured in accordance with CCITT Recommendation O.9 [8], subclause 2.7:
1) at 1 024 kHz: ≥ 40 dB;
2) 1 024 kHz to 30 MHz: minimum value decreasing from 40 dB at 20 dB/decade.
n) The output port of the layer 1 interface shall meet the jitter and wander requirements defined in
figure 1d and table 0d.
Peak-to-peak jitter
and wander amplitude
(log scale)
Characteristics at a
A
0
typical frame aligner
A
1
Slope equivalent to 20 dB/decade
A
2
0
f f f f f
0
1 2 3 4
Jitter frequency (log scale)
Figure 1d: Lower limit of maximum tolerable input jitter and wander
Table 0d: Parameter values for input jitter and wander tolerance
Peak-to-peak amplitude Frequency
(unit interval UI) (Hz)
A A A f f f f f
0 1 2 0 1 2 3 4
-5 3 3 3
36,9 1,5 0,2 1,2 x 10 20 2,4 x 10 18 x 10 100 x 10
(18 μs)
NOTE 1: 1 UI = 488 ns.
NOTE 2: The value for A represents a relative phase deviation between the incoming signal and the
0
internal timing local signal derived from the reference clock.
NOTE 3: The wander requirement of 26 μs takes into account the application of SDH transmission
systems providing the transparent digital link between the AN and LE.
The tolerance to jitter of interface inputs shall conform with the requirements for low-Q clock
recovery according to CCITT Recommendation G.823 [7]. Interface outputs shall conform with the
requirements for high-Q clock recovery according to CCITT Recommendation G.823 [7] even with
tolerable input jitter according to low-Q clock recovery, i.e. a jitter reduction capability is required in
the frequency area between high-Q and low-Q cut off frequencies for the jitter transfer. This
requirement supports independence of the interface implementation from application in networks
using different clock recovery Q factors as well as with an additional digital link to increase the
range of the interface.
o) The outer conductor of the coaxial pair or the screen of the symmetrical pair shall be connected to
the signal ground both at the input and at the output port of the layer 1 interface."
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Page 21, clause 5
Replace the complete text of clause 5 by:
"The functional and procedural requirements of the interface shall conform to ETS 300 167 [2],
2 048 kbit/s case. The CRC-4 procedure specified in ETS 300 167 [2] shall be applied including the Cyclic
Redundancy Check (CRC) error reporting using bit E in the CRC-multiframe.
This clause identifies the layer 1 requirements from the referenced specifications including the specific
characteristics and parameters.
The specific requirements and characteristics from ETS 300 167 [2] and CCITT Recommendation G.704
are listed in table 0e. Where the requirements do not fit into the table, only the reference is shown and the
detailed requirements are given below.
Table 0e: Functional requirements from ETS 300 167 [2] or CCITT Recommendation G.704
Item Requirements based on ETS 300 167 or AN LE
CCITT Recommendation G.704
a) Frame length 2.3.1/G.704
b) Allocation of bits 1 to 8 2.3.2/G.704
c) Use of bit 1 for CRC-4 2.3.3.1/G.704,
but covered by items d) and e)
d) Allocation of bit 1 2.3.3.2/G.704 and 2.3.3.3/G.704
e) Use of bit 1 of CRC-4 multiframe 2.3.3.4/G.704
f) Cyclic redundancy check 2.3.3.5/G.704
g) Frame structure 5.1.1/G.704
Detailed requirements for indicated items in table 0e:
a) The frame length shall be 256 bits, numbered 1 to 256. The frame repetition rate shall be 8 kHz.
b) The allocation of bits number 1 to 8 of the frame shall be as defined in table 0f.
Table 0f: Allocation of bits 1 to 8 of the frame
Bit number
Alternate frames 1234 5678
Frame containing the frame S 001 1011
i
alignment signal note 1 Frame alignment signal
Frame not containing the frame S 1A S S S S S
i a4 a5 a6 a7 a8
alignment signal note 1 note 2 note 3 note 4
NOTE 1: This bit shall be used for the CRC-4 procedure.
NOTE 2: This bit shall be fixed at ONE.
NOTE 3: This bit shall be used for the Remote Alarm Indication (RAI). In undisturbed operation, set to
ZERO; in alarm condition, set to ONE.
NOTE 4: These bits are not used in the V5.1 interface and shall be set to ONE.
d) The allocation of bits 1 to 8 of the frame shall be as defined in table 0g.
Each CRC-4 multiframe, which is composed of 16 frames numbered 0 to 15, shall be divided into
two 8-frame Sub-Multiframes (SMF), designated SMF I and SMF II which signifies their respective
order of occurrence within the CRC-4 multiframe structure. The SMF shall be of the CRC-4 block
size (i.e. 2 048 bits).
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Table 0g: CRC-4 multiframe structure
Sub- Frame Bits 1 to 8 of the frame
multiframe number
(SMF) 1 2345678
0 C 0 0 1 1 0 1 1
1
1 0 1 A S S S S S
a4 a5 a6 a7 a8
2 C 0 0 1 1 0 1 1
2
I 3 0 1 S S S S S
A
a4 a5 a6 a7 a8
4 C 0 0 1 1 0 1 1
3
5 1 1 A S S S S S
a4 a5 a6 a7 a8
6 C 0 0 1 1 0 1 1
4
7 0 1 A S S S S S
a4 a5 a6 a7 a8
Multiframe
8 C 0 0 1 1 0 1 1
1
9 1 1 A S S S S S
a4 a5 a6 a7 a8
10 C 0 0 1 1 0 1 1
2
II 11 1 1 A S S S S S
a4 a5 a6 a7 a8
12 C 0 0 1 1 0 1 1
3
13 E 1 A S S S S S
a4 a5 a6 a7 a8
14 C 0 0 1 1 0 1 1
4
15 E 1 A S S S S S
a4 a5 a6 a7 a8
Notation: C to C = CRC-4 bits
1 4
E = CRC-4 error indication bits
A = Remote Alarm Indication (RAI)
e) In those frames containing the frame alignment signal, bit 1 shall be used to transmit the CRC-4
bits. There are four CRC-4 bits, designated C , C , C and C in each SMF.
1 2 3 4
In those frames not containing the frame alignment signal, bit 1 shall be used to transmit the 6-bit
CRC-4 multiframe alignment signal and two CRC-4 error indication bits (E).
The CRC-4 multiframe alignment signal shall have the form 001011.
The E-bits shall be used to indicate received faulty sub-multiframes by setting the binary state of
one E-bit from ONE to ZERO for each faulty sub-multiframe. Any delay between the detection of an
faulty sub-multiframe and the setting of the E-bit that indicates the error state shall be less than 1
second.
The E-bits shall always be taken into account even if the SMF which contains them is found to be
faulty.
f) Cyclic redundancy check
Multiplication/division process:
a particular CRC-4 word, located in sub-multiframe N, shall be the reminder after multiplication by
4 4
x and then division (modulo 2) by the generator polynomial x + x + 1, of the polynomial
representation of sub-multiframe (N - 1). When representing the contents of the check block as a
polynomial, the first bit in the block, i.e. frame 0, bit 1 or frame 8, bit 1, shall be the most significant
bit. Similarly, C shall be the most significant bit of the remainder and C the least significant bit of
1 4
the remainder.
Encoding procedure:
1) the CRC-4 bits in the SMF shall be replaced by ZEROs;
2) the SMF shall then be acted upon by the multiplication/division process specified above;
3) the remainder resulting from the multiplication/division process shall be stored, ready for
insertion into the respective CRC-4 locations of the next SMF.
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SIST ETS 300 324-1:1997/A1:1997
Page 14
ETS 300 324-1: February 1994/A1: January 1996
Decoding procedure:
1) a received SMF shall be acted upon by the multiplication/division process specifies above,
after having its CRC-
...
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