1、Recommendation T/CS 41-01 (Vienna, 1982) SIGNAL AND SIGNALLING MESSAGE NAMES AND MEANINGS Recommendation proposed by Working Group T/WG 1 1 “Switching and Signalling” (CS) Text of the Recommendation adopted by the “Teleconmiiriications” Commission : “The European Conference of Postal and Telecommuni
2、cations Administrations, considering - that in automatic working, the transmission of specific signals between exchanges and between terminal equipment - that systems based on signalling messages are currently being introduced; - that at present, several standardised signalling systems with individu
3、ally specified signal and signalling message - that consequently, a considerable number of names are used to identify signals and signalling messages and that - that new services may require new signalling procedures with new signals and signalling messages, and exchanges has been common practice fo
4、r a long period of time; meanings are employed in the European network; confiision may result in an undesirable interpretation of specifications; recommends - to the members of the CEPT, the use of appropriate sets of signals and signalling messages with names and - that new signals and signalling m
5、essages with their names and meanings are made known for insertion in this meanings as specified below; Recommendation.” 1. GENERAL 1.1. Scope This Recommendation is drawn up recognising that most standardised sigiialling systems used in the European network provide the same basic features. Some sig
6、nals and signalling messages have the same name and the same meaning in all systems. Others differ to varying degrees. The Recoininendation is intended as a common reference to show equivalence and difference in detail as applicable. The name and the allocated meaning do not completely define a sign
7、al or signalling message and their use. For that, the transmission method, the coding and the precise signalling procedures need be specified as well. In accordance with Recommendation T/CS O1 -02 i, these characteristics are usually dealt with in separate specifications. While standardised signalli
8、ng systems may vary considerable with regard to trans- mission method, coding and signalling procedures, the differences with regard to the individual signals and signalling messages are largely confined to the size of the repertoire of such signals and signalling messages which each system provides
9、. Signalling systems based on data transmission and computer technology, e.g. CCITT systems No. 6 and No. 7, are designed to provide a large number of signals and signalling messages. Other signalling systems may be optimised for use with a limited repertoire. This Recommendation is based on the com
10、prehensive set of signals and signalling messages adopted for the telephoiie mer part of CCITT common channel sigrinllig systems No. 7 2 J and System R2 3 channel associated sigiialliig. Extensions are made which cover other standardised systems of interest to European Administrations. 1.2. Terminol
11、ogy The naming and hence the meaning of signalling messages and signals depends in a general sense on their fiinctions. Specific requirements relating to the use of signals and Signalling messages are, in principle, not covered by this Recommendation, although in exceptional cases explanatory notes
12、on their use or genera- tion have been added. Due regard should be given to terminology, as in telecommunications the terms signnllitzg and sigiial pertain to a particular concept. In accordance with CCITT Recommendation Q.9 4 the following dejiiitioris apply. CEPT T/CS*4L-OL*E 2 232b4L4 0004747 7 T
13、ICS 41-01 E Page 2 2. 2.1. 2.1.1. 2.1.2. 2.2. Signalling (a) The exchange of information (other than by speech) specifically concerned with the Set-up, release and other control of calls, and network management, in automatic telecommunications operations. (b) A qualification implying an action as de
14、fined above, e.g. Signalling channel Signalling procedure - equipment - relation - information - route - link - system - message - time slot Signal (general sense) Aggregate of waves propagated along a transmission channel and intended to act on a receiving unit. Note: General sense applies only to
15、the area of telecommunications. The ordinary dictionary sense is still wider, viz. A precoiicerted or intelligible sign conveying injortnatioii or direction at a distarice. Signal (in signalling applications) A transferable element of information relating to a particular circuit, a particular transa
16、ction or to network management. Note 1; A signal as defined above may be generated by a change of state. Note 2; A qualification may precede the term, e.g. answer sigrial. The qualification represents the name of the signal and generally refers to the kind of information the signal conveys or its ma
17、in function. A great many such qualifications are defined in standard signalling system specifications. Signal (in SDL) A flow of data conveying information to a process. Signalling message An assembly of signalling information pertaining to a call, management transaction, etc. comprising also eleme
18、nts for delimitation, sequencing and error control, that is transferred as an entity. Forward signal A signal, used for the Set-up, release or other control of a connection, sent in the same direction as call Set-up. Backward signal A signal, used for the Set-up, release or other control of a connec
19、tion, sent in the opposite direction to call Set-up. The concept as illustrated by the above definitions implies that signals and signalling messages convey information, the signalling information, which in general represents the meaning (semantics) of the signal or the signailing message concerned.
20、 The signalling information content of a signalling message may be functionally subdivided. Such subdivisions may represent a signal OS an indicator which identifies certain previously agreed upon information. A particular subdivision, the label, contains signalling information for the routing of th
21、e message and the identification of the transaction or circuit concerned. USER PART MESSAGES FOR COMMON CHANNEL INTER-EXCHANGE SIGNALLING This list of signalling messages is based on a fiinctional grouping. It is expected that national applications wiil require further messages, in addition to the i
22、nternationally defined ones indicated in the following. Therefore, some groups as yet may only contain one message. Forward address message group This message group includes messages sent in the forward direction containing address information. Signals from Section 4.1. may be included. Initial-addr
23、ess message A type of message sent first in the forward direction at call Set-up. It contains address information and other information relating to the routing and handling of the call. Subsequent-address message A type of message sent in the forward direction subsequent to the initial address messa
24、ge and containing , further address information. Forward Set-up message group This message group includes messages sent in the forward direction subsequent to address messages, containing further information for call Set-up. Signals from Section 4.1. may be included. O Edition of May 15, 1986 2.2.1
25、* 2.3. 2.4. 2.4.1. 2.4.2. 2.5. 2.5. 2.6. 2.7. 3. 3.1. 3.1.1. 3.1.2. 3.2. 3.2.1. Contmty message A type of message containing a continuity signal. Backward set-up request message group This message group includes messages sent in the backward direction requesting further information for call set-up.
26、Signals from Section 4.2. may be included. Successful backward set-up information message group This message group includes messages sent in the backward direction containing information relating to a successful call set-up. Signals from Section 4.2. may be included. Address-cottiplete message A typ
27、e of message containing a signal indicating that all address signals required for routing the call to the called party have been received and giving, possibly, additional information relating to the called line. Charging message A type of message containing charging information. Unsuccessful backwar
28、d set-up information message group This message group includes messages sent in the backward direction containing information relating to an iinsuccessfiil call set-up. Signals from Section 4.2. inay be included. UisuccessJi1l-call-atteit message A message containing a signal from Section 4.2. relat
29、ing to an unsuccessful call set-up. Call-supervision message group Messages containing a signal, from Section 4.3., relating to the supervision of the call. Circuit-supervision message group Messages containing a signal from Section 4.4., relating to the supervision of the circuit. PARTICULAR SUBDIV
30、ISIONS OF COMMON CHANNEL INTER-EXCHANGE SIGNALLING MESSAGES Signalling information relating to services The service information provides the highest level of discrimination between different sets of signalling messages. It contains the following components. Service indicator Information used to iden
31、tify the user part to which the signalling message belongs. National ildcator Information used for discrimination between international and national messages. In the case of national messages, it may, for example, also be used for discrimination between different label alternatives for national use.
32、 Note: The national indicator is examined together with the service indicator by the message distribution function, so that, for example, in the case of a user part having an international and a national version, it is possible to use the same service indicator code and to use the national indicator
33、 to discriminate between the two versions. Moreover, considering that two codings of the national indicator are reserved for national use, it will be possible to define up to 32 national user parts (even though the use of the national indicator to discriminate diferent national routing labels, as in
34、dicated in CCITT 4.704 5, will also be possible). Label Information within a signalling message used for its routing and for identifying the particular transaction with which the message is associated. The transaction may concern a particular circuit which then is identified by the label. Destinatio
35、n-poitit code Information identifying the signalling point to which the message is to be routed. Orgiitatng-point code Information identifying the signalling point from which the message has originated. 3.2.2. Edition of May 15, 1986 Page 4 3.2.3. 3.3. 3.3.1. 3.3.2. 3.3.3. 4. 4.1. 4.1.1. 4.1.2. 4.1.
36、3. 4.1.4. 4.1.5. 4.1.6. 4.1.7. Circuit- identijication code Information identifying the particular circuit among those interconnecting the exchange, with which the signalling originating point is associated, and the exchange with which the signalling destination point is associated. Message format i
37、dentifiers Heading Information discriminating, as applicable, between different groups or individual types of messages within the set of messages identified by the service information. The heading is split into two levels. The first level discriminates between different groups. The second level eith
38、er discriminates between different message types or contains a signal. Field-length indicator Information associated with and indicating the length of a variable length field. Field indicator Information associated with and indicating the presence or absence of an optional field. USER PART SIGNALS F
39、OR COMMON CHANNEL INTER-EXCHANGE SIGNALLING Forward-set-up signals Address signal A cail set-up signal sent in the forward direction. The signal contains one element of information (digit O, 1,2 . 9, code 11 or code 12) about the called partys number or is the end-of-pulsing (sending terminated, ST)
40、 signal. For each call, a succession of address signals is sent (see CCITT Recommendations Q.101 6 and 4.107 End-ofpulsing (sending terrniriated, ST) signal An address signal sent in the forward direction indicating that there are no more address signals to follow. Nature-of-address indicator Inform
41、ation sent in the forward direction indicating whether the address is an international, national significant or subscriber number. Nature-of-circuit indicator Information sent in the forward direction about the nature of the circuit or any preceding circuits already engaged in the connection, e.g. -
42、 a satellite circuit, or - no satellite circuit. An international exchange receiving this information will use it (in combination with the appropriate part of the address information) to determine the nature of the outgoing circuit to be chosen. Echo-suppressor indicator Information sent in the forw
43、ard direction indicating whether or not an outgoing half-echo suppressor is included in the connection. Calling-partys-category indicator Information sent in the forward direction about the category of the calling party and, in the case of semi-automatic calls, about the service language to be spoke
44、n by the incoming, delay and assistance operators. The following categories are provided: - operator, - ordinary calling subscriber, - calling subscriber with priority, - data call, - test call. Contiriiiity-check itidicator Information sent in the forward direction indicating whether or not a conti
45、nuity check will be performed on the circuit concerned or is being/has been performed on a previous circuit in the connection. 71). Edition of May 15, 1986 4.1.8. 4.1.9. 4.1.10. 4.1.11. 4.2. 4.2.1. 4.2.2. 4.2.3. 4.2.4. 4.2.5. 4.2.6. 4.2.7. 4.2.8. 4.2.9. 4.2.10. 4.2.11. CEPT T/CS*43-O3*E 2 m 2326434
46、0004750 7 m TICS 41-01 E Page 5 Calling-line-identity Information sent in the forward direction indicating the national significant number and, when required, the country code of the calling party. Cnllirtg-litie-ieitity-uriavnilable signal A signal sent in the forward direction indicating that the
47、identity of the calling line is not available. Contimiity signal A signal sent in the forward direction indicating continuity of the preceding No. 7 speech circuit(s) as well as of the selected speech circuit connecting to the following international exchange, including verification of the speech pa
48、th across the exchange with the specified degree of reliability. Contitiiiity failure signal A signal sent in the forward direction indicating failure of continuity of the No. 7 speech circuit. Backward-set-up signais Callirig-liie-identity-request signal A signal sent in the backward direction requ
49、esting transfer of the calling line identity from the originating exchange. Address-cornjdete signal A signal sent in the backward direction indicating that all the address signals required for routing the call to the called party have been received and that no called-partys-line-condition signals (electrical) will be sent. Adress-complete signal, charge A signal sent in the backward direction indicating that all the address signals required for routing the call to the called party have been received, that no called-partys-line-condition signals (electr
