1、CEPT T/TE*Ob=01*E m 2326434 0009703 8 (3 TTE06-01 Page E 1 Recommendation T/TE 06-01 (Innsbruck 1981, revised at Cannes 1983, Montpellier 1984, Nice 1985 and Edinburgh 1988) VIDEOTEX SERVICE Recommendation proposed by the Working Group T/GT 10 “Terminal equipment” (TE) Revised text of the Recommenda
2、tion adopted by the “Telecommunications” Commission : The European Conference of Posts and Telecommunications Administrations, considering - the work undertaken within CEPT with a view to harmonising international telecommunication services as well - studies carried out within the framework of quest
3、ion CD 7, - the possible benefit to the expansion of the Videotex Service in providing a stable environment for the full - the possibility that some Administrations require a lower cost basic service and others an enhanced service with - the need for a common standard which will enable Administratio
4、ns who wish to do so to confidently adopt the - the need to leave the way open to add new facilities as technology progresses in a way which preserves investments as equipment, commercial exploitation of existing services already implemented, extra facilities, “harmonised enhanced” service or up gra
5、de a basic service to the “harmonised enhanced” service, in basic services or enhanced services, recommends that 1. In order to facilitate international access between Videotex Services in Europe, 1.1. International access to national Videotex Services should be via PTT provided international gatewa
6、ys. 1.2. International gateways should intercommunicate using the communication protocols to be adopted by CEPT, the information being coded according to data syntax described in Annex A, with the range of information transmitted restricted to conform to the service reference model as described in A
7、nnex B. 1.3. Administrations should ensure that the coded information is transcoded as necessary in order to provide the best possible display on the terminals in use in that country. In addition, Administrations may provide identification of user and billing. 2. In order to recognise existing syste
8、ms and to harmonise further development of Videotex Services, 2.1. Systems offering a basic service shall be based on one of the four profiles described in Annex C (see Figure 1 .a 2.2. An enhanced service of foreseen facilities is optional but where they are provided they shall conform to the (T/TE
9、 06-01). standards referred to in Figure 1.b (T/TE 06-01). 2.3. New enhanced services which are either as yet unforseen or not yet defined in sufficient detail in Annex B to make a recommendation at this stage shall be formulated such that they are (1) based on one of the four basic building blocks
10、and harmonised service or based on one of the four basic building blocks and be able to display informations generated by systems using the harmonised enhanced service standard; (2) able to be adopted without modifications to any parameters defined in the references given in Figure 1.b (T/TE 06-01).
11、 - Edition of September 15, 1989 CEPT T/TE*Ob-Ol*E , 232b414 OOO702 T TITE 06-o1 E Page 2 2.4. a) Either new optional enhanced services which are either as yet unforeseen or not yet defined in sufficient detail in Annex B shall not be added to a system providing the basic service without also includ
12、ing the “harmonised enhanced” service referred to in Figure lb (T/TE 06-01). b) Or new optional enhanced services which are either as yet unforeseen or not yet defined in sufficient detail in Annex B (Figure IC (T/TE 06-01) may be adopted without also adopting the facilities of the “har- monised enh
13、anced” service standard referred to in Figure lb (T/TE 06-01). In this case at least full compatibility with CEPT Recommendation T/TE 06-01 version Innsbruck (May 1981) shall be assumed. However it is preferable for both lb (T/TE 06-01) and IC (T/TE 06-01) in Figure 1 (T/TE 06-01) to be adopted if m
14、aximum inter-working between services is to be achieved at the earliest possible time. 3. Studies should continue on - New enhanced services which are not yet defined in sufficient detail in Annex B (photographic mode) so as - International communication protocol. to arrive at a common standard for
15、them. 4. In order to harmonise the interface to “external computers” for communication between external computers and Videotex centres, Administrations should adopt the data syntax described in Annex A for the coding of informa- tion and common protocols for the other layers (possibly those referred
16、 to in 1.2 above). Edition of September 15, 1989 - CEPT T/TE*Ob-OL*E = 2326414 O009703 1 1.1.2. 6.2.2. 8. 1.3.2. 1 o. 1.4.1. and 1.4.2. (simultaneously) 1.4.3. to 1.4.5. 1.5. to 1.9. 4. 5. T/TE06-01 E Page 3 Edition of September 15, 1989 i FUTURE HORIZON Figure IC (T/TE 06-01) Standard for new enhan
17、ced services as yet unforeseen or not yet defined in services (optional) - must be based on one of the four basic building blocks and ?harmonised enhanced? service, - must be based on one of the four basic building blocks and be able to display information generated by systems - must be able to be a
18、dopted without modifications to any parameters defined in the references given in Figure 1 .b or using the harmonised enhanced service standard, (T/TE 06-01). IST HORIZON A A Figure lb (T/TE 06-01) L-l Standard for the 6?hannonised enhanced? service (optional) II II II II II see section 2.4. (option
19、al) II II II / JJ Figure la (T/TE 06-01) f7 FLEXIBLE INITIAL BUILDING BLOCKS (ALTERNATIVES) - / -/ -/ / BASIC SERVICE LEVEL Figure 1 (T/TE 06-01). CEPT Recommendation on enhanced Videotex Service and its relationship with existing basic Videotex Service systems and new as yet undefined facilities. C
20、EPT T/TE*Ob-OL*E 2326414 0009704 3 T/TE 06-01 E Page 5 VIDEOTEX PRESENTATION LAYER DATA SYNTAX O ANNEX A PART O. PART 1. PART 2. PART 3. PART 4. PART 5. PART 6. PART 7. PART 8. GENERAL 1. Introduction 2. References 3. Definitions ALPHA MOSAIC DISPLAYS 1. Description 2. Repertory 3. Coding structure
21、Appendix A. Identification system Appendix B. GEOMETRIC DISPLAYS Refer to Recommendation T/TE 06-02 E PHOTOGRAPHIC DISPLAYS 1. Introduction 2. 3. 4. Photographic table header unit 5. Photographic table transfer unit Appendix A3A. DPCM image coding - one dimensional Appendix B3B. DCT image coding - t
22、wo dimensional DEFINE DYNAMICALLY REDEFINABLE CHARACTER SETS 1. Introduction 2. DRCS Header units 3. Pattern transfer units 4. Coding methods 5. 6. Applicability of attributes DEFINE COLOUR 1. Introduction 2. Colour system extension 3. Coding of redefinable colours DEFINE FORMAT 1. Introduction 3. D
23、efaults TRANSPARENTDATA Refer to Recommendation T/TE 06-03 E RESET 1. Introduction 2. Coding structure 3. Functional description and coding Examples of time dependency in the unified alphamosaic model Photographic pixel header unit (PPHU) Photographic pixel transfer unit (PFTU) Designation and invoc
24、ation of DRCS 2. Coding This P nex is an integral part of th Edition of September 15, 1989 Recommendation TITE 06-01 E. - r- - - CEPT T/TE*Ob-OL*E 2326434 O009705 5 T/TE06-01 E Page 6 ANNEX A PART 9. TELESOFTWARE (Continued) Refer to Recommendation TITE 06-04 E PART 10. TERMINAL FACILITY TDENTIFIER
25、(TF1) Refer to Recommendation T/TE 06-05 E PART 11. TIMING CONTROL 1. Introduction 2. Wait ANNEX B CEPT Videotex Service Reference Model: Conformance ANNEX C CEPT Videotex Service Reference Model: Profiles Appendix List of abbreviations Edition of September 15, 1989 CEPT T/TE*Ob-OL*E m 2326434 00097
26、06 i m T/TE06-01 E Annex A. Part O. Page 1 PART O . GENERAL Contents 1 . 1.1. 1.1.1. 1.1.2. 1.2. 1.2.1. 1.2.2. 2 . 3 . INTRODUCTION . 3 Identifcation of Data Types . 3 Use of Default Values 3 Display Principles . 4 Dejined Display Area 4 Coding Principles 3 Display Structure 4 REFERENCES 4 DEFINITIO
27、NS 4 Edition of September 15. 1989 4 VPCE VSCE CEPT T/TE*Ob-OL*E m 232h434 0009707 9 m VPCE 1. 0 T/TE 06-01 E Annex A, Part O, Page 3 INTRODUCTION VIDEOTEX systems are text communication systems with the capability of a given level of pictorial representation and a repertoire of display attributes.
28、The text and the pictures obtained are intended to be displayed using the current television (TV) raster standards of the different countries. Videotex Services will be provided in different ways in different countries. The Videotex Services may be a distributed network of independent computers or a
29、 hierarchy of computers with external databases or a mixture of both. It is probable that in all countries Videotex terminals will primarily access the Videotex Services via the switched telephone network, over which data is transmitted to a terminal which generates displays. Three types of display
30、have been identified and are described and defined in this recommendation: Part 1, Alphamosaic. Part 2. Geometric. Part 3. Photographic. Other types of display may be defined in the future. Each type of display may be used simultaneously, though data for each type of display is Separated during tran
31、smission. The way in which data is used to generate a display may be modified by “management data”. Management data may affect more than one type of display. Coding Principles 1.1.1. Identification of Data Types Different types of display data and management data are separated into different “Videot
32、ex Presentation Data Elements” (VPDEs) during transmission. “Videotex Presentation Data Elements” (VPDEs) are made up of two parts: “Videotex Presentation Control Element” (VPCE) which identifies the type of data and “Videotex Service Control Element” (VSCE) which contains the data. O Edition of Sep
33、tember 15, 1989 CEPT T/TE*Db-OL*E 2326434 0009708 O T/TE06-01 E Annex A, Part O, Page 4 It is anticipated that some terminals will only be able to process data which conforms to these default values, to simplify their operation these terminals may ignore such data, unless the parameters describing t
34、hat data are omitted (implying that the data conforms to the default). It is therefore recommended that when a parameter is equal to the default value that field is not transmitted, if it is transmitted then the response of the terminal is not guaranteed. 1.2. Display Principles 1.2.1. 1.2.2. Define
35、d Display Area The defined display area is a rectangular area of the screen within which the text and pictorial information is displayed. The ratio of the width to the height (aspect ratio) of this area should be 4:3. For the alphamosaic display this area is composed of a defined number of rows each
36、 with a defned number of character positions. The default is 24 rows of 40 character positions. For the geometric display the bottom lefthand corner of the defined display area is addressed as (O, O) and the upper righthand corner is defined as (i, 0.75). The photographic display area also maps to t
37、he same area. The top lefthand pixel of the photographic display area is addressed as (i, 1). The possibility of defining different aspect ratios is for further study. Display Structure The theoretical structure of the display consists of the following layers in order of precedence: 1. Alphamosaic c
38、haracter foreground and background layers (see Part l., Section 1.2.), 2. Geometric layer or layers (see Part 2.), 3. Photographic layer (see Part 3.), 4. Full screen background layer (see Part i.), 5. Any other video source. Changing the display structure is for further study. 2. REFERENCES This do
39、cument is intended to be compatible with the following recommendations and standards: CCITT Recommendation T.50 International alphabet No. 5. CCITT Recommendation F.300 Vidotex Service. CCITT Recommendation T. 100 International information exchange for interactive Videotex. CCITT Recommendation T. 1
40、 O 1, Annex C International Interworking for Videotex Services. IS0 Standard 2022 (Rev. 86) Code Extension Techniques for use with the IS0 7-bit and 8-bit coded character set. IS0 Standard 6937 Information processing - coded character sets for text communication. IS0 Standard 6429.2 Draft standard -
41、 additional control functions for character imaging devices. CEPT Recommendation T/SF 59 E International Videotex Service. 3. DEFINITIONS BIT-COMBINATION Bit-combination is an ordered set of bits that represents a character. BORDER AREA Border area is that part of the display screen (visible display
42、) which is outside the defined display area. (See Note and Figure AO-1 (T/TE 06-01) below.) CONTROL CHARACTER Control character is a control function, the coded representation of which consists of a single bit-combina- tion. Edition of September 15, 1989 CEPT T/TE*Ob-OL*E 232b4L4 0009709 2 TITE 06-0
43、1 E Annex A. Part O, Page 5 CONTROL FUNCTION Control function is an action that affects the recording, processing, transmission or interpretation of data. The coded representation of a control function consists of one or more bit-combinations. DEFINED DISPLAY AREA The defined display area is a recta
44、ngular area of the screen within which the text and pictorial information is displayed (see Figure AO-1 (T/TE 06-01) and Section 1.2.1.). Full Visible Display Border Area Defined Display Area Figure AO-1 (T/TE 06-01). Full Visible Display, Border Area and Defined Display Area. Note. The default form
45、at of defined display area for the alphamosaic option is given in Part 1 ., Section 1.1.2. GRAPHIC CODE EXTENSION Graphic code extension is the method of encoding graphic characters in excess of those which may be represented by the code combinations of the basic code table. Alternative sets of 94 c
46、haracters may be designated by means of shift functions. Edition of September 15, 1989 CEPT T/TE*Ob-OI*E 232b4L4 O009710 9 T/TE 06-01 E Annex A. Part 1 . Page 1 PART 1 . ALPHAMOSAIC DISPLAYS Contents 1 . DESCRIPTION 5 1.1. Introduction 5 1.1.1. DeJnitions 5 1.1.2. Format 5 1.1.4. Format Efectors 5 1
47、.1.5. Attributes 6 1.1.6. Device Control Functions 6 1.2.1. Description 6 1.2.3. Layered Structure 1 . 1.1.3. Characters . 5 . 1.2. Theoretical Terminal Model . 6 1.2.2. Operation of “Parallel” and “Serial” Mode Controls 6 1.2.4. Action of Attributes on Layers 1 1.3. Defined Attributes and Qualified
48、 Areas 8 1.3.1. FOREGROUND COLOUR . a 1.3.2. BACKGROUND COLOUR . 8 . . 1.3.3. LINED 8 1.3.4. SIZE 8 1.3.5. FLASH 8 1.3.6. CONCEAL 8 1.3.1. INVERT . 9 1.3.9. MARKED . 9 1.3.10. PROTECTED 9 1.3.1 1 . Scrolling Area 9 1.3.12. Colour Tables 9 1.4. 9 1.5. Defaults 10 1.5.1. Default Initiation 10 1.5.3. D
49、efault Colour Look-up Tables 10 1.5.4. Default Colour Map 11 1 S.5. Default Device Controls 11 1.5.6. Default Graphic Sets 11 2 . REPERTORY 13 2.1. Character Repertoire 13 2.1.2. Mosaic Graphics 22 1.3.8. WINDOW/BOX 9 . . . Rules for the Action of the SIZE Attribute . 1.5.2. Default Setting of Attributes . 10 . . O 2.1.1. Alphanumeric Characters 13 2.2. Format Effector Repertoire 34 2.3. Attribute Control Repertoire . 35 2.3.1. FOREGROUND COLOUR Controls . 35 2.3.2. BACKGROUND COLOUR Controls . 31 . 2.3.3, LINING Controls 38 2.3.4. SIZEControls 38 2.3.5. FLASH Controls 38 2.3
