1、Recommendation T.563 TERMINAL CHARACTERISTICS FOR GROUP 4 FACSIMILE APPARATUS CONTENTS 1 General 2 3 4 Mixed mode capabilities 5 Communicat ions 6 Network-related requirements I Indicators Scope of Recommendations concerning Group 4 facsimile apparatus General characteristics of the apparatus 8 Acce
2、ss to facsimile MHS 9 Implementation of apparatus Annex A - Guaranteed reproducible area for Group 4 apparatus conforming to Recommendation T.563 Appendix I - Communication environment establishment The CCITT, considering (a) that Recommendation T.2 refers to Group 1 type apparatus for IS0 A4 docume
3、nt transmission over a telephone-type circuit in approximately six minutes; (b) (c) that Recommendation T.3 refers to Group 2 type apparatus for IS0 A4 document transmission that Recommendation T.4 refers to Group 3 type apparatus for IS0 A4 document transmission over a telephone-type circuit in app
4、roximately three minutes; over a telephone- type circuit in approximately one minute; (d) that there is a demand for Group 4 apparatus which incorporates means for reducing the transmission time and assures essentially error-free reception of the document; (e) that telematic terminals including Grou
5、p 4 facsimile apparatus are to be standardized, taking into account the commonality among these terminals; (f) that there is a demand for mixed mode of operation where both facsimile coded information and character coded information can be treated within a page by the same apparatus; unanimously dec
6、lares that Group 4 facsimile apparatus as defined in Recommendation T.0 should be designed and operated according to the following standard. 1 General 1.1 Group 4 facsimile apparatus is used mainly on public data networks (PDN) including circuit- switched, packet-switched, and the integrated service
7、s digital network (ISDN). The apparatus may be also used on the public switched telephone network (PSTN) where an appropriate modulation process will be utilized. CCITT FASCICLE VII.7 * YB62591 0512549 5 Fascicle W.7 - Rec. T.563 - CCITT FASCICLE VII.7 * 4862591 0532550 L 1.2 The procedures used wit
8、h Group 4 facsimile apparatus enable it to transmit and reproduce image coded information essentially without transmission errors. 1.3 Group 4 facsimile apparatus has the means for reducing the redundant information in facsimile signals prior to transmission. 1.4 e.g. grey scale image or colour imag
9、e are for further study. The basic image type of the Group 4 facsimile apparatus is black and white. Other image types, 1.5 There are three classes of Group 4 facsimile terminals: - Class I - Minimum requirement is a terminal able to send and receive documents con- taining facsimile encoded informat
10、ion (in accordance with Recommendations T.6, T.503 and T.521). - Class II - Minimum requirement is a terminal able to transmit documents which are facsimile encoded (in accordance with Recommendations T.6, T.503 and T.521). In addition, the terminal must be capable of receiving documents which are f
11、acsimile coded (in accor- dance with Recommendations T.6, T.503 and T.521), teletex coded (in accordance with the basic coded character repertoire as defined in Recommendations T.60 and T.61), and also mixed-mode documents (in accordance with Recommendation T.56 1). - Class III - Minimum requirement
12、 is a terminal which is capable of generating, trans- mitting and receiving facsimile coded document (in accordance with the Recommen- dations T.6, T.503 and T.521), teletex coded document (in accordance with the basic coded character repertoire as defined in Recommendations T.60 and TAI), and mixed
13、-mode docu- ments (in accordance with Recommendation T.561), see Note. Nofe - The above definitions are. extracted from Study Group I where “terminal“ is used instead of “apparatus“. 2 Scope of Recommendations concerning Group 4 facsimile apparatus 2.1 This Recommendation defines the general aspects
14、 of Group 4 facsimile apparatus. 2.2 The rules to be followed in the Group 4 facsimile services are defined in Recommen- dation F.184. 2.3 dation T.6. The Group 4 facsimile coding scheme and facsimile control functions are defined in Recommen- 2.4 Terminal supporting Group 4 facsimile mode of operat
15、ion communicates with unique procedures that are described as follows: a) the interface to the physical network is defined in this Recommendation (see Note); b) the transport end-to-end control procedure is defined in Recommendation T.70; c) Group 4 facsimile control procedures are defined in Recomm
16、endation T.62; d) Group 4 facsimile communication application profile is defined in Recommendation T.52 1; e) Group 4 facsimile document application profile is defined in Recommendation T.503. Note - Recommendation T.71 may be applicable for PSTN operation. 2.5 When operating as mixed-mode terminals
17、, Recommendation T.561 applies. 2.6 When operating as basic teletex terminals, Recommendations T.60 and T.61 apply. 216 Fascicle W.7 - Rec. T.563 CCITT FASCICLE VII.7 * m 4862593 0532553 3 m 3 General characteristics of the apparatus 3.1 Basic characteristics 3.1.1 The Group 4 facsimile apparatus pr
18、ovides the means for direct document transmission from any subscriber to any other subscriber. 3.1.2 All apparatus participating in the international Group 4 facsimile service has to be compa- tible with each other at the basic level defined in this Recommendation. Additional Operational functions m
19、ay be invoked. 3.1.3 The range of data rates is described in 0 6. Detailed arrangements on a national level are left to the Administrations concerned, as it is recognized that national implementation of the Group 4 facsimile service on various types of network may involve national operation at diffe
20、rent data throughput rates. 3.1.4 The page is the basis for facsimile message formatting and transmission. Both A4 and North American paper formats are taken into account. 3.1.5 Facsimile coding schemes are applies in order to reduce the redundant information in facsimile signals prior to transmissi
21、on. 3.1.6 The apparatus must have to ability to reproduce facsimile messages. The content, layout and format of facsimile messages must be identical at the transmitting and receiving apparatus. 3.1.7 The reproducible area is defined within which facsimile messages are assured to be reproduced (see 0
22、 3.2.6). 3.1.8 The Group 4 facsimile apparatus should provide means for automatic reception. In addition Class II/III apparatus should provide means for automatic reception of teletex and mixed mode docu- ments. 3.1.9 All classes of Group 4 facsimile apparatus shall incorporate the functions defined
23、 as basic for the Group 4 facsimile service in 0 3.2 below. In addition, optional functions can be incorpo- rated. In this Recommendation, the optional functions are divided into CCITT standardized options and nationally and/or privately specified options. 3.2 Basic funciions 3.2.1 Group 4 facsimile
24、 mode of operation shall be capable of handling: a) b) c) d) the control function associated with the basic facsimile coding scheme as defined in communication application profile as defined in Recommendation T.521; document application profile as defined in Recommendation T.503; the basic facsimile
25、 coding scheme as defined in Recommendation T.6; Recommendation T.6. 3.2.2 All classes of Group 4 apparatus shall have the following provisions for facsimile messages: a) b) provision for scanning the documents to be transmitted (see 0 3.2.5); provision for receiving and presenting hard or soft copi
26、es of the documents. 3.2.2.1 In addition Group 4 class II apparatus shall have provision for receiving and displaying basic teletex and mixed mode documents. 3.2.2.2 In addition to the requirements for Group 4 Class II apparatus, Class III apparatus shall have provisions for generating and transmitt
27、ing basic teletex and mixed mode documents. 3.2.3 Basic page formatting funciions are as follows a) vertical page orientation; b) c) paper size of IS0 A4; reproducible area/printable area is defined taking into account IS0 A4 and North American paper formats and IS0 standard 3535. Fascicle W.7 - Rec
28、. T.563 277 li -. . CCITT FASCICLE VII.7 * I 4862571 0512552 5 m 200 240 300 400 3.2.4 Terminal identification the identification are given in Recommendation F.184. Each Group 4 facsimile apparatus should be equiped with a unique identification. Details of 1728 1728 2048 2432 2048 1728 2074 2074 245
29、8 2918 2450 2074 2592 2592 3072 3648 3072 2592 3456 3456 4096 4 864 4096 3456 3.2.5 Scanning The message area should be scanned in the same direction in the transmitter and receiver. Viewing the message area in a vertical plane, the picture elements shall be processed as if the scanning direction we
30、re from left to right with subsequent scans adjacent to and below the previous scan. Scan line length (m) (P) Paper width (mn) (Q) 3.2.6 3.2.6.1 Sometimes paper length may not be specified, because the paper end is detected by paper scanning. 3.2.6.2 The size of the guaranteed reproducible area for
31、IS0 A4 paper size is shown in Annex A to this Recommendation. Page size and reproducible area 219.46 219.46 260.10 308.86 260.10 219.46 2 10 215.9 250 297 257 182 3.2.7 Table 1/T.563. Group 4 facsimile transmission pel density (resolution) requirements The Group 4 facsimile resolution requirements a
32、nd their tolerances are given in TABLE 1/T.563 Resolution (pelc/25.4 mm) 1 Horzontal and vertical tolerance X I 200 x 200 240 x 240 300 x 300 400 x 400 fl fl fl fl Centre line referencing will be sued for paper positioning. Each page will be positioned on the scanner so that the centre line is in re
33、gistration with the value: (number of pels/line)/2. (For further study.) Specific values for the number of pels per line, scan line length and nominal number of scan lines per page are given in Tables 2a/T.563 and 2b/T.563 for all the Group 4 resolutions for IS0 A4, North American, IS0 B4, IS0 A3, J
34、apanese legal and Japanese letter paper. TABLE 2a/T.563 Number of pels and can line length for different paper sizes 1 IS0 A4 1 North 1 IS0 B4 1 IS0 A3 1 Jaymm;e 1 Japanese I American letter Number of picture elements along a scan line Re so lut i on (pels/25.4 mn) I I I l I I I I P-Q I 9.46 I 3.56
35、I 10.10 1 11.86 I 3.10 I 37.46 I 278 - Fascicle V11.7 - Rec. T.563 CCITT FASCICLE VII.7 t* = 48b2591 0512553 7 Haninal paper length (mu) 297 279.4 . 364 257 Resolution (pels/25.4 mn) Pels per line (A) 14 21 28 1? (15.1) (18.1) (22.1) (29.1) 40 48 60 80 47 56 70 94 (41.1) (49.1) (61.1) (81.1) (48.1)
36、(57.1) (71.1) (95.1) 12 15 18 24 14 7 177 221 294 (13.1) (16.1) (19.1) (25.1) (148.1) (178.1) (222.1) (295.1) TABLE 2b/T.563 Nominal number of scan lines for different paper sizes IS0 A3 I IS0 E4 IS0 A4 2339 2806 3508 4677 North American 4400 I _ Nminal nrmber of scan lines per page for each pel- tr
37、ansmission density Resolution (pels/25.4 mo) 2780 3335 4169 . 5559 3301 3969 4961 6614 200 240 300 400 5732 353 420 Table 3/T.563 specifies the blanking procedure for all of the Group 4 paper sizes. An equal number of pels on the left and right side of the page are set to white to -fit the paper for
38、mat. - Figure l/T.563 illustrates the blanking procedure for IS0 A4 and North American paper. The same procedure is used for the other paper formats. TABLE 3/T.563 Blanking and address reference point for different paper sizes aper size Pels per each paper size line Total line length (w) Blanking ma
39、rgin (pels 1 1654 1984 2480 3308 (B ) 37 45 56 14 IS0 A4 1728 2074 2592 3456 219.46 219.46 219.46 219.46 200 x 200 240 X 240 300 X 300 400 X 400 (38.1) (46.1) (57.1) (75.1) North American 1728 2074 2592 3456 1700 2040 2550 3400 219.46 219.46 219.46 219.46 200 x 200 240 X 240 300 X 300 400 X 400 2048
40、 2458 3072 4096 1968 2362 2952 3936 IS0 84 IS0 A3 200 x 200 240 X 240 300 X 300 400 X 400 200 x 200 240 X 240 300 X 300 400 X 400 260.10 260.10 260.10 260.10 308.86 308.86 308.86 308.86 2432 2918 3648 4864 2338 2806 3508 4676 2048 2458 3072 4096 2024 2428 3036 4048 Japanese legal North American 260.
41、10 260.10 260.10 260.10 219.46 219.46 219.46 219.46 200 x 200 240 X 240 300 X 300 400 X 400 200 x 200 240 X 240 300 X 300 2592 400 X 400 3456 1434 1720 2150 2868 Note - The pels as defined in the blanking margin section (blanking margin A and B are shown in Figure l/T.563) are equivalent to the disc
42、arded pels defined in Recommendation T.503. *? =- Fascicle W.7 - Rec. T.563 279 “.i_ CCITT FASCICLE VII-7 * = 4862593 0532554 9 4 1 -1 Total line lenath (Pl + -+ North American line length ia) I FIGURE 1/T.563 Reference point and blanking margins The raster point is the upper left corner of an IS0 p
43、age is used as a reference for portrait mode character printing. This raster point, termed the (1,l) raster reference point, is used as a starting point for determining character margins and positions. This is also illustrated in Figure l/T.563. 3.2.8 Group 4 facsimile class slruciure Table 4/T.563
44、shows the class structure of Group 4 facsimile apparatus. 280 Fascicle WI.7 - Rec. T.563 CCITT FASCICLE VII-7 * m 4Bb2593 0532555 O m Class Standard pel transmission density (peW25.4 mn) TABLE 4/T.563 Class structure I II III (see Note 1) (see Note 1) (see Note 1) 200 200 and 300 200 and 300 (see No
45、te 2) (see Note 2) Dptional pel transmission density (pels/25.4 m) Pel conversion capability in standard 200 and/or 300 240 and/or 400 240 and/or 400 and/or 400 (see Note 3) (see Note 3) not required yes yes Teletex Mixed mde Page memory not required reception only yes not required reception only ye
46、s not required yes yes Note I - Administrations may determine which class with options to be used for their national service. Standardization work has to continue with the goal of achieving a uniform standard. Use of docwent application profile Use of cmnication application profile Note 2 - When ope
47、rating as a mixed mode terminal per Recommendation T.561, the pel receiving density of 240 pels/25.4 mm is required. see Table WT.563 see Table 5/T.563 Note 3 - To achieve a high service quality, the pel density of the scanner and printer should be grater that or equal to the transmission pel densit
48、y. This requirement is waived for a terminal which has a scanner or printer with a pel density of 240 x 240 pels per 25.4 mm and can communicate at 300 pels per 25.4 mm. In this case, the 240 x 240 pels per 25.4 mm terminal will exceptionally meet the standard Class II/III requirement. Note 4 - When
49、 a resolution conversion is necessary, the conversion is performed by the apparatus which minimizes the transmission cost and time. An exception would be a 240 x 240 pels per 25.4 mm terminal transmitting to a 300 x 300 pels per 25.4 mm terminal which is operating at the standard transmission quality. Note 5 - Pel conversion algorithms should aim at low impairment of the quality and are for further study. 3.2.9 Facsimile coding scheme 3.2.9.1 In order to reduce the redundant information in facsimile signals, the basic facsimile codi
