1、STD*ITU-T RECMN T-33-ENGL L99b 48b257L Ob220b2 275 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU T.33 (07/96) SERIES T: TERMINAL EQUIPMENTS AND PROTOCOLS FOR TELEMATIC SERVICES Facsimile routing utilizing the Subaddress ITU-T Recommendation T.33 (Previou
2、sly OXT Recommendation,) - STD-ITU-T RECMN T-33-ENGL L77b = 4b2571 Ob220b3 LOL m FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and
3、issuing Recommen- dations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendation
4、s on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). ITU-T Recommendation T.33 was prepared by -T Study Group 8 (1993-1996) and was approved under the WTSC Resolution No. 1 procedur
5、e on the 3rd of July 1996. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1996 All rights reserved. No part of this publication may be reproduced or utilized in any form
6、 or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. STDWITU-T RECMN T-33-ENGL 177b 9 Li862591 Ob220bLi 048 m CONTENTS 1 Introduction and scope . 3 Definitions Rules for use of delimiters in Subaddress . Encoding of the Subaddr
7、ess Facsimile Information Field . 2 Normative References 4 Representation of Subaddress Representation of Subaddress Facsimile Information Field . 5.1 Example of Subaddress FiF construction . Decoding of the Subaddress Facsimile Information Field . 4.1 4.2 5 6 Annex A - Description of Backus-Naur No
8、tation . Annex B - Outline of the Facsimile Routing Procedure . B.l Definitions Procedure for Facsimile Routing Flow diagram of Routing Procedure . Representation of Facsimile Address Representation of Facsimile Address on printed materials . Appendix II -Examples of Facsimile Address and Subaddress
9、 Examples of Facsimile Address Additional examples of Subaddress FIF coding . B.2 B.3 Appendix I - Representation of Facsimile Address I . 1 1.2 II.1 11.2 Page 1 1 2 2 2 2 3 3 4 6 6 6 7 8 10 10 10 11 11 11 Recommendation T.33 (07196) 1 STD-ITU-T RECMN T-33-ENGL 177b 48b2571 Ob220b5 T4 H SUMMARY This
10、 Recommendation defines application rules for the routing of Group 3 facsimile messages using the Subaddress (SUB) signal as defined in Recommendation T.30. The aspects which are addressed include placement of telephone address components (phone extensions and secondary dialling numbers) within the
11、SUB frame, encoding and decoding rules, and an outline of the facsimile routing procedure. KEYWORDS Facsimile, Group 3, Routing. 11 Recommendation T.33 (0796) Recommendation T.33 FACSIMILE ROUTING UTILIZING THE SUBADDRESS Geneva, 1996) 1 Introduction and scope There is a requirement within the marke
12、tplace to provide reliable routing of facsimile messages which are received by a Group 3 facsimile terminal and then require further routing to reach the final recipient. Environments where this requirement exists include Local Area Networks, facsimile mailbox systems and facsimile services. Related
13、 applications may entail use of telephone extensions or secondary telephone numbers to enable this routing. This Recommendation is intended to address these requirements. This Recommendation defines optional encoding methods for the routing of Group 3 facsimile messages using the Subaddress (SUB) si
14、gnal as defined in the Recommendation T.30. This Recommendation addresses the following aspects of facsimile message routing within the Group 3 facsimile procedure: 0 Definition of a Subaddress representation whose contents may include phone extensions, a phone number or a combination of these eleme
15、nts. Placement, encoding and decoding of telephone number and extension information within the Facsimile Information Frame of the Subaddress signal. Outline and a flow diagram of a facsimile routing procedure. Definitions of the method and user interface to be used for the entry of telephone number
16、and subaddress information by an operator of a facsimile device or facsimile software are beyond the scope of this Recommendation. The methods by which a facsimile message may be routed after reception by a facsimile terminal are also beyond the scope of this Recommendation. 2 Normative References T
17、he following Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations aand other references are subject to revision: all users of thi
18、s Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. - CCITT Recommendation E. 123 (1988), Notation for nation
19、al and international phone Numbers. - CCITT Recommendation E.164 (1991), Numbering plan for the ISDN era. - CCIT Recommendation T.6 (1988), Facsimile coding schemes and coding controlfinctions for Group 4 facsimile apparatus. - ITU-T Recommendation T.4 (1993), Standardization of Group 3 facsimile ap
20、paratus for document transmission. - ITU-T Recommendation T.30 (1993), Procedures for document facsimile transmission in the general switched telephone network. - CCIT Recommendation T.434 (1992). Binaryfile transfer format for the telematic services. - ITU-T Recommendation F.551 (1993), Service Rec
21、ommendation for the telematic file transfer within Telefax 3, Telefax 4, teletex services and messaging handling services. Recommendation T.33 (07/96) 1 - STD-ITU-T RECMN T-33-ENGL L97b 4b2.571 b220bi 857 m 3 Definitions For the purposes of this Recommendation, the following definitions apply: 3.1 t
22、elephone number: This is a multiple digit string with dial modifiers as defined in Recommendation E.123. 3.2 extension: For the purposes of this Recommendation, this is defined as string of one or more digits representing a unique destination assigned to a specific person for receipt of facsimile me
23、ssages. This is commonly known as a “phone extension“. 3.3 more extensions. telephone address: This is an address entity which shall include a telephone number and may include one or 3.4 of the telephone number in the facsimile procedure. second stage telephone number: This is a telephone number whi
24、ch is reserved for use after the initial dialling 3.5 further routing in the Group 3 facsimile procedure. subaddress signal (SUB): This is a signal defined in Recommendation T.30 which is intended to provide 3.6 subaddress content: This is information content which may be transferred using the Subad
25、dress signal (SUB) within Group 3 facsimile Recommendation T.30. For purposes of this Recommendation, the information content to be transferred may consist of one or more telephone extensions, a second stage dial number or a combination of these elements. 3.7 subaddress facsimile information field:
26、This is a character string whose size, encoding and permissible characters are defined generically in Recommendation T.30. As of the publication date of this Recommendation, these permissible characters are numeric digits 0-9 and the *, # and SPACE characters and the total length of the Subaddress F
27、IF is 20 octets. The SPACE character is reserved for use in padding to fill up to the full permitted length of the subaddress. 3.8 per Recommendations T.4 and T.30 and optionally per Recommendations T.6, T.30, T.434 and F.55 1. facsimile message: This is any information which can be communicated bet
28、ween Group 3 facsimile terminals 3.9 grammar. A definition of these production rules is contained within Annex A. BNF: All objects defined in this Recommendation are described using a Backus Naur Form (BNF) style of 4 Representation of Subaddress 4.1 Rules for use of delimiters in Subaddress For con
29、sistency with current trends in use of telephone keypad characters as expressed in Recommendation E.164 and other ITU-T Recommendations, the # character shall be used within the subaddress FIF as a delimiter between multiple extensions and two consecutive # characters (Le. #) shall be used as a deli
30、miter between telephone addresses. The * character shall be reserved for user applications. For compact representation, the first character to be represented in a Subaddress FIF shall be the first numeric digit for the case of an extension and a single # for the case of a telephone address. 4.2 Repr
31、esentation of Subaddress Facsimile Information Field The Subaddress Content to be placed within the Subaddress Facsimile Information Field (FIF) shall be represented as defined in this subclause for compliance with this Recommendation. The representation of the Subaddress Content and its components
32、is provided in BNF form. The information content of the Subaddress FIF may be composed of the following components which were defined in clause 3: := Extension 43econdSage-Num ber := Second Stage Telephone Number 2 Recommendation T.33 (07/96) STD-ITU-T RECMN T-33-ENGL L77b 9 48b2571 Db22Db8 793 SSSS
33、#234567890#1234 The combination of a Second Stage Telephone Number and the extensions associated with that telephone number make up a Telephone Address, which is signified in the BNF notation below as a Complete Address. One or more occurrences of these components may be encoded within the Subaddres
34、s FIF per the rules defined below. Components := d)igit) #) := := #) := #Complete-Address := I # Subaddress FIF Representation := dirst-Address# 5 Encoding of the Subaddress Facsimile Information Field This clause defines how to encode and place Subaddress Content within the Facsimile Information Fi
35、eld (FIF) of the SUI3 signal within the Group 3 facsimile procedure. The sending facsimile terminal shall build the FIF for the SUB signal. The routing information to be placed within the Subaddress FIF shall be in the form of Subaddress Content as defined in clause 4. The octets of the Subaddress F
36、IF shall be coded per Table 3.30. The Subaddress Content shall be right justified and placed in the least significant octets of the SUB FW frame. Per Recommendation T.30, the unused octets in the FIF shall be padded from the left and filled with the “space“ character. The least significant bit of th
37、e least significant digit shall be the first bit transmitted. 5.1 Example of Subaddress FIF construction An example is provided to illustrate the process of constructing a Subaddress FIF and the order of transmission of SUB octets. This example assumes a fixed length FIF of 20 octets, where padding
38、characters used to fill up the SUB FIF to its full length. In the sample case, suppose that the Subaddress Content to be placed in the FIF frame is as follows: #1234567890#1234 In placing the Subaddress content into the FIF octets, the SPACE character (shown below as “S) shall be used to pad from th
39、e left as shown in Table 1: TABLE 1.33 Placement of octets in Subaddress FiF Recommendation T.33 (07/96) 3 STD-ITU-T RECMN T-33-ENGL L99b L1db257L Ob22067 b2T 9 20 In hexadecimal representation, this can be represented as shown below in Figure 1: 20 20 20 23 31 32 33 34 35 36 37 38 39 40 23 31 32 33
40、 34 Mast significant octet Least significant octet I 00110100 Last bit transmitted FIGURE, 1m.33 Order of transmission of SUB FIF octets T0825320-96/401 T First bit transmitted According to the rules of Recommendation T.30, the least significant octet ( or (O01 1 0100) in this example) is the first
41、octet transmitted and the least significant bit of the least significant octet is transmitted first. In turn, the most significant octet ( or (O010 0000) in this example) is the last octet transmitted. 6 Decoding of the Subaddress Facsimile Information Field If subaddress information has been exchan
42、ged during the Group 3 facsimile procedure, the receiving facsimile terminal shall receive the optional SUB signal during T.30 negotiations. The Facsimile Information Field for the SUB signal shall contain the Subaddress octets. The Subaddress Content may be extracted from the SUB FiF by processing
43、octets from left to right, ignoring leading “space“ characters used for padding. The Subaddress Content may then be decoded for routing purposes, As defined in 4.2, the Subaddress Content may consist of one or more phone extensions, one or more second stage phone numbers or combinations of these com
44、ponents. Where the subaddress FIF includes phone extensions, it may be assumed that these extensions are associated with the preceding telephone number. Where the first components in the SUB FIF are one or more extensions, these are associated with the previously dialled telephone number. The formal
45、 representation of Subaddress Content has been defined in 4.2. The rules for the decoding of Subaddress Content shall include the following: The first non-SPACE character to be represented in a Subaddress FIF shall be the first numeric digit for the case of an extension and a single # for the case o
46、f a telephone address. A single # is the delimiter between multiple extensions. Two consecutive characters are the delimiters between multiple addresses. A state diagram for the decoding of the Subaddress FIF is shown in Figure 2: 4 Recommendation T.33 (07/96) START c? eo Terminate # SST I Consume L
47、eading Spaces Terminate Ext I # Consume a End Collect SST char Consume # and Terminate Ext Consume # 1 eoi Collect Ext char (Note) SST Second Stage Telephone Number Ext Phone Extension eo End of Input NOTE - Implementors may check the validity of the collected address information from the Subaddress
48、 FIF frame. FIGURE 2iT.33 State diagram for decoding Subaddress FIF 5 Recommendation T.33 (07/96) Annex A Description of Backus-Naur Notation (This annex forms an integral part of this Recommendation) The following provides a description of the Backus-Naur style syntax which is used in the body of t
49、his Recommendation. Symbol Description of use literal _ . .- I A token (or component) is noted by a literal. This is the production assignment operator. This symbol is used to separate alternative tokens or groups of tokens. A non-terminal token is noted by a literal enclosed by the e” and 5” characters. 11 I An optional token or group of tokens is enclosed by the “, and “1” characters. A group of tokens enclosed in “” and “” may be repeated O, 1 or more times. Annex B Outline of the Facsimile Routing Procedure (This annex forms an inte
