1、INTERNATIONAL TELECOMMUNICATION UNIONITU-T H.248TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITUAnnex F(11/2000)SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services CommunicationproceduresFacsimile, Text Conversation and CallDiscrimination packagesAnnex FCAUTION !PREPUBLIS
2、HED RECOMMENDATIONThis prepublication is an unedited version of a recently approved Recommendation.It will be replaced by the published version after editing. Therefore, there will bedifferences between this prepublication and the published version.FOREWORDThe International Telecommunication Union (
3、ITU) is the United Nations specialized agency in the field oftelecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ ofITU. ITU-T is responsible for studying technical, operating and tariff questions and issuingRecommendations on them with a view to standard
4、izing 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 turn, produce Recommendations onthese topics.The approval of ITU-T Recommendations is covered
5、 by the procedure laid down in WTSC Resolution 1.In some areas of information technology which fall within ITU-Ts purview, the necessary standards areprepared on a collaborative basis with ISO and IEC.NOTEIn this Recommendation, the expression “Administration“ is used for conciseness to indicate bot
6、h atelecommunication administration and a recognized operating agency.INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation mayinvolve the use of a claimed Intellectual Property Right. ITU takes no position concerning the eviden
7、ce,validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or othersoutside of the Recommendation development process.As of the date of approval of this Recommendation, ITU had/had not received notice of intellectualproperty, protected by patents, which may
8、 be required to implement this Recommendation. However,implementors are cautioned that this may not represent the latest information and are therefore stronglyurged to consult the TSB patent database. ITU 2001All rights reserved. No part of this publication may be reproduced or utilized in any form
9、or by any means,electronic or mechanical, including photocopying and microfilm, without permission in writing from theITU.ITU-T H.248/Annex F (11/2000) Prepublished version 1H.248 ANNEX FFacsimile, Text Conversation and Call Discrimination packagesCONTENTSPageF.1 Summary. 3F.2 Scope . 3F.3 Definitio
10、ns 3F.3.1 Hexadecimal octet coding. 3F.3.2 Hexadecimal octet sequence . 4F.4 References. 4F.5 FAX/Textphone/Modem Tones Detection Package. 5F.5.1 Properties 5F.5.2 Events 5F.5.3 Signals. 6F.5.4 Statistics 6F.5.5 Procedures. 6F.6 Text Conversation package . 6F.6.1 Properties 7F.6.2 Events 9F.6.3 Sign
11、als . 9F.6.4 Statistics 9F.6.5 Procedures. 10F.7 Text Telephone package . 12F.7.1 Properties 14F.7.2 Events 18F.7.3 Signals . 18F.7.4 Statistics 18F.7.5 Procedures . 19F.8 Call Type Discrimination package . 21F.8.1 Properties 21ITU-T H.248/Annex F (11/2000) Prepublished version 2F.8.2 Events 23PageF
12、.8.3 Signals. 27F.8.4 Statistics 29F.8.5 Procedures . 29F.9 Fax package 31F.9.1 Properties 31F.9.2 Events 33F.9.3 Signals . 34F.9.4 Statistics 34F.9.5 Procedures . 34F.10 IP Fax package 35F.10.1 Properties 35F.10.2 Events 37F.10.3 Signals . 38F.10.4 Statistics 38F.10.5 Procedures . 38ITU-T H.248/Ann
13、ex F (11/2000) Prepublished version 3F.1 SummaryH.248 Annex F describes packages for fax, text telephone, call type discrimination, and data calldetection for use with the H.248 Gateway Control Protocol. As defined in H.248, a “package“ is anextension to H.248 that supports specific behaviour.The pa
14、ckages are intended for control over gateway functions for transport of facsimile or textconversation between different network environments. Extensions can be made for other kinds ofdata transport. The Call Type Discrimination package defines control and monitoring of a PSTN line forthe signalling
15、protocols used in the beginning of a session of data transmission for fax, texttelephony or data. The Text Telephone package defines control of a PSTN text telephone session in any ofthe modes supported by the automoding text telephone Recommendation V.18. The Fax package defines control of a PSTN f
16、ax transmission. The Fax/Textphone/Modem Tones Detection package defines control over a terminationfor detection of any signals from a fax, text telephone or data modem during a connectionin voice mode. The Text Conversation package defines control over a real time interactive textconversation sessi
17、on using a universal presentation format and transferred with a transportmethod from a multimedia protocol in any network environment. The IP Fax package defines control over facsimile transmission in a packet network.F.2 ScopeH.248 Annex F describes packages for the ITU-T H.248 gateway protocol rel
18、ated to data ortelematic services. With terminations implementing these packages, a gateway is expected to handleinitial modem negotiations, and the communication in voice, fax and text telephone call types. Itcontains:Package “ftmd“ for general detection of signals on a fixed telephone line indicat
19、ing a possiblerequest to enter some data related mode.Package “ctyp“ for general call discrimination to sort out if a call should be handled as voice, fax,text telephone or modem data, and perform the initial negotiation.Package “txp“ for communicating with text telephones in the telephone network.P
20、ackage “fax“ for communication with facsimile in the telephone network.Package “txc“ for general text conversation in other environments.Package “ipfax“ for fax transmission in IP networks.F.3 DefinitionsF.3.1 Hexadecimal octet codingHexadecimal octet coding is a means for representing a string of o
21、ctets as a string of hexadecimaldigits, with two digits representing each octet.Each octet is issued by the DTE or DCE in the same time sequence as transmitted on the GSTNline, with no intervening characters.ITU-T H.248/Annex F (11/2000) Prepublished version 4For each octet, the 8-bit sequence is en
22、coded as two hexadecimal digits. Bit 0 is the firsttransmitted; bit 7 is the last.Bits 7-4 are encoded as the first hexadecimal digit, with bit 7 as MSB and bit 4 as LSB. Bits 3-0 areencoded as the second hexadecimal digit, with bit 3 as MSB and bit 0 as LSB.Examples:Octet bit pattern(time order as
23、specified in V.8 and V.8bis)HexadecimalcodingT.50 codes00011011 D8 4/4, 3/811100100 27 3/2, 3/710000011 10100010 11001000 00001001 C1451390 4/3, 3/1, 3/4, 3/5, 3/1, 3/3, 3/9, 3/0F.3.2 Hexadecimal octet sequenceA hexadecimal octet sequence is an even number of hexadecimal digits, terminated by a (T.5
24、0 0/13) character.F.4 References1 IETF RFC 1889: Schulzrinne, H., et al, RTP: A Transport Protocol for Real-TimeApplications, January 1996.2 ITU-T Recommendation T.30 (07/96) - Procedures for document facsimile transmission inthe general switched telephone network.3 ITU-T Recommendation T.38 (06/98)
25、 - Procedures for real-time Group 3 facsimilecommunication over IP networks.4 ITU-T Recommendation V.8 (2000) - Procedures for starting sessions of data transmissionover the public switched telephone network.5 ITU-T Recommendation V.8bis (2000) - Procedures for the identification and selection ofcom
26、mon modes of operation between data circuit-termination equipments (DCEs).6 ITU-T Recommendation V.18 (2000) - Operational and interworking requirements forDCES operating in the text telephone mode.7 ITU-T Recommendation V.25 (1996) - Automatic answering equipment and/or parallelautomatic calling eq
27、uipment on the general switched telephone network.8 ITU-T Recommendation T.140 (1998) - Text conversation protocol for multimediaapplication. With Amendment 1 (2000).9 ITU-T Recommendation H.323 Annex G (2000) - Text Conversation and Text SET (2000).10 IETF G. Hellstrm, “RTP Payload for Text Convers
28、ation“, Internet Engineering TaskForce, RFC 2793. (2000)11 ITU-T Recommendation T.134 (1998) - Text Chat Application Entity.12 ITU-T Recommendation V.17 (02/91), Recommendation V.17 (02/91) - A 2-wire modemfor facsimile applications with rates up to 14 400 bit/s.ITU-T H.248/Annex F (11/2000) Prepubl
29、ished version 513 ITU-T Recommendation V.27ter (11/88) - 4800/2400 bits per second modem standardizedfor use in the general switched telephone network.14 ITU-T Recommendation V.21 (11/88) - 300 bits per second duplex modem standardizedfor use in the general switched telephone network.15 ITU-T Recomm
30、endation V.23 (11/88) - 600/1200-baud modem standardized for use in thegeneral switched telephone network.16 ITU-T Recommendation V.34 (02/91) - A duplex modem operating at data signalling ratesof up to 14 400 bit/s for use on the general switched telephone network and on leasedpoint-to-point 2-wire
31、 telephone-type circuit.17 ITU-T Recommendation V.90 (09/98) - A digital modem and analogue modem pair for useon the Public Switched Telephone Network (PSTN) at data signalling rates of up to56 000 bit/s downstream and up to 33 600 bit/s upstream.18 ITU-T Recommendation V.61 (08/96) - A simultaneous
32、 voice plus data modem, operatingat a voice plus data signalling rate of 4 800 bit/s, with optional automatic switching todata-only signalling rates of up to 14 400 bit/s, for use on the General Switched .19 ITU-T Recommendation T.37 (06/98) - Procedures for the transfer of facsimile data viastore a
33、nd forward on the Internet.20 ISO/IEC 10646-1 (1993) - Universal Multiple Octet Coded Character Set.21 ITU-T Recommendation T.50 (1992) - International Reference Alphabet (IRA) (formerlyInternational Alphabet No. 5 or IA5) - Information technology - 7-bit coded character setfor information interchan
34、ge.22 ITU-T H.323 Annex D (1998) - Facsimile.F.5 FAX/Textphone/Modem Tones Detection PackagePackageID: ftmd, 0x000EVersion: 1Extends: tonedet version 1This package defines an event to detect the presence of data traffic (fax, textphone or modem) on aline. The main intention of this event may be used
35、 to effect the compression option on the line sothat an audio codec capable of transmitting modem signals can be invoked to handle the connectionwhen needed. This Package extends the possible values of tone id in the “start tone detected“ event.Note that there is no discrimination between tones from
36、 this package. If discrimination is desired,the Call Type Discrimination package should be invoked.F.5.1 PropertiesNone.F.5.2 EventsEvents are defined as for the tone detection package.F.5.2.1 Additional tone id valuedtfm, 0x0039ITU-T H.248/Annex F (11/2000) Prepublished version 6This tone id is gen
37、erated when any of the following tones are detected.“Tone“ Description Applicable toCNG a T.30 fax calling FaxV21flag a V21 tone and flags FaxCIV18 a V.8 CI with V.18 call function TextphoneXCI a V.18 XCI TextphoneV18txp a V.18 “txp“ TextphoneBelltone a Bell 103 carrier, either the high or the low f
38、requencychannel (as defined in V.18)TextphoneBaudot a Baudot initial tone and character (as def. in V.18) TextphoneEdt an EDT initial tone and character (as def. in V.18) TextphoneCIdata a V.8 CI with any data call function DataCT a V.25 calling tone Text and DataCIfax a V.8 CI with facsimile call f
39、unction FaxV21tone a V.21 carrier, either the high or the low frequencychannelText and DataV23tone a V.23 carrier, either the high or the low frequencychannelText and dataV8bis a V.8bis modem handshaking signal Fax, Text and DataANS V.25 ANS, equivalent to T.30 CED from answeringterminalFax, Text an
40、d DataANSAM V.8 ANSam Fax, Text and DataF.5.3 SignalsNone.F.5.4 StatisticsNone.F.5.5 ProceduresNone.F.6 Text Conversation packagePackage Name: Text ConversationPackageID: txc (0x00F)Version: 1Extends: NoneDescription:The Text Conversation package is intended for enabling real time text conversation
41、betweenterminals in different networks or multimedia environments. This package includes the mechanismsITU-T H.248/Annex F (11/2000) Prepublished version 7needed to transport T.140 text conversation streams 8 in multimedia environments. The transportmechanism will be different for each environment w
42、here the package is used.F.6.1 PropertiesF.6.1.1 Text buffering timePropertyID: bufftime (0x0001)Type: IntegerPossible values: 0-500Defined in: LocalControlCharacteristics: Read/WriteDescription:This property indicates the time in ms that T.140 8 data shall be collected beforetransmission in order t
43、o keep overhead from text low. In low bit rate IP networks, avalue of 300 ms is recommended. In environments with low overhead or high bitrates this property should have the value 0 enabling immediate transmission ofentered characters.F.6.1.2 Text termination connection statePropertyID: connstate (0
44、x0002)Type: EnumerationPossible values:Idle (0x0001) for no connection effortsPrepare (0x0002) for being known in the termination and readyto accept connections.(the text capability is offered in session requests)Initiate (0x0003) for taking the initiative to establish a textconnection opening a tex
45、t channelAccept (0x0004) for accepting an incoming request for a textsessionDeny (0x0005) for denying an incoming text connect requestConnected (0x0006) for established connection in text modeDefined in: TerminationStateCharacteristics: Read/WriteDescription:The connection state property is used to
46、register text capability, request a textconnection, and reflect details of the achieved text connection. For transport methodshaving separate channel control procedures, managed by the MGC, only a subset ofthe values is used: Idle, Prepare, Connected.F.6.1.3 Text User IdentityPropertyID: txuserid (0
47、x0003)Type: StringPossible value: String of up to 64 characters in Unicode UTF-8 20Defined in: LocalControlCharacteristics: Read/WriteITU-T H.248/Annex F (11/2000) Prepublished version 8Description:This parameter holds the optional remote User Identity parameter of a T.140 8 textconversation session
48、, retrieved from the session.F.6.1.4 Text TransportPropertyID: trpt (0x0004)Type: EnumerationPossible values:H224 (0x0001) for H.224 Client ID=2 in H.320AL1 (0x0002) for AL1 in H.324TCP (0x0003) for TCP as in H.323 Annex G 9RTP/T.140 (0x0004) for RTP with T.140 8 as in H.323Annex G 9 or IETF SIPRTP/
49、RED/T.140 (0x0005) for RTP with T.140 and redundancycoding RED as in H.323 Annex G orIETF SIPT.134 (0x0006) for T.134 in the T.120 environment 11Unassigned (0x0007) When no transport protocol is assignedDefined in: LocalControlCharacteristics: Read/WriteDescription: The Transport parameter reflects the transport mechanism selected for the TextConversation termination. When the media description has the full capability ofdescribing sessions including the transport mechanism, this parameter is implied bythe
