📄 rfc804.txt
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CCITT Draft Recommendation T.4 PAGE 6 01010011 8 50 01010100 8 51 01010101 8 52 00100100 8 53 00100101 8 54 01011000 8 55 01011001 8 56 01011010 8 57 01011011 8 58 01001010 8 59 01001011 8 60 00110010 8 61 00110011 8 62 00110100 8 63 CCITT Draft Recommendation T.4 PAGE 7 Table 1b. Make Up White Codes Code Lng Run --------------------------- 11011 5 64 10010 5 128 010111 6 192 0110111 7 256 00110110 8 320 00110111 8 384 01100100 8 448 01100101 8 512 01101000 8 576 01100111 8 640 011001100 9 704 011001101 9 768 011010010 9 832 011010011 9 896 011010100 9 960 011010101 9 1024 011010110 9 1088 011010111 9 1152 011011000 9 1216 011011001 9 1280 011011010 9 1344 011011011 9 1408 010011000 9 1472 010011001 9 1536 010011010 9 1600 011000 6 1664 010011011 9 1728 CCITT Draft Recommendation T.4 PAGE 8 Table 2a. Terminating Black Codes Code Lng Run --------------------------- 0000110111 10 0 010 3 1 11 2 2 10 2 3 011 3 4 0011 4 5 0010 4 6 00011 5 7 000101 6 8 000100 6 9 0000100 7 10 0000101 7 11 0000111 7 12 00000100 8 13 00000111 8 14 000011000 9 15 0000010111 10 16 0000011000 10 17 0000001000 10 18 00001100111 11 19 00001101000 11 20 00001101100 11 21 00000110111 11 22 00000101000 11 23 00000010111 11 24 00000011000 11 25 000011001010 12 26 000011001011 12 27 000011001100 12 28 000011001101 12 29 000001101000 12 30 000001101001 12 31 000001101010 12 32 000001101011 12 33 000011010010 12 34 000011010011 12 35 000011010100 12 36 000011010101 12 37 000011010110 12 38 000011010111 12 39 000001101100 12 40 000001101101 12 41 000011011010 12 42 000011011011 12 43 000001010100 12 44 000001010101 12 45 000001010110 12 46 000001010111 12 47 000001100100 12 48 000001100101 12 49 CCITT Draft Recommendation T.4 PAGE 9 000001010010 12 50 000001010011 12 51 000000100100 12 52 000000110111 12 53 000000111000 12 54 000000100111 12 55 000000101000 12 56 000001011000 12 57 000001011001 12 58 000000101011 12 59 000000101100 12 60 000001011010 12 61 000001100110 12 62 000001100111 12 63 CCITT Draft Recommendation T.4 PAGE 10 Table 2b. Make Up Black Codes Code Lng Run --------------------------- 0000001111 10 64 000011001000 12 128 000011001001 12 192 000001011011 12 256 000000110011 12 320 000000110100 12 384 000000110101 12 448 0000001101100 13 512 0000001101101 13 576 0000001001010 13 640 0000001001011 13 704 0000001001100 13 768 0000001001101 13 832 0000001110010 13 896 0000001110011 13 960 0000001110100 13 1024 0000001110101 13 1088 0000001110110 13 1152 0000001110111 13 1216 0000001010010 13 1280 0000001010011 13 1344 0000001010100 13 1408 0000001010101 13 1472 0000001011010 13 1536 0000001011011 13 1600 0000001100100 13 1664 0000001100101 13 1728 CCITT Draft Recommendation T.4 PAGE 11Note: It is recognized that machines exist which accommodatelarger paper widths whilst maintaining the standardhorizontal resolution. This option has been provided for bythe addition of the Make Up Code Set defined as follows: Table 3. Extended Make Up Codes (Black and White) Code Lng Run --------------------------- 00000001000 11 1792 00000001100 11 1856 00000001101 11 1920 000000010010 12 1984 000000010011 12 2048 000000010100 12 2112 000000010101 12 2176 000000010110 12 2240 000000010111 12 2304 000000011100 12 2368 000000011101 12 2432 000000011110 12 2496 000000011111 12 2560 The identification and choice of either the standardcode table or the extended code table is to be made in thepre-message (Phase B) portion of the T.30 controlprocedures.4.2 Two dimensional coding scheme The one-dimensional coding scheme defined in 4.1 may beextended as an option to a two-dimensional scheme. This isthe subject of further study.5. Modulation and demodulation method It is provisionally agreed that Group 3 apparatusoperating on the general switched telephone network shallutilize the modulation scrambler, equalization and timingsignals defined in Recommendation V.27ter, specifically inthe preamble and 2, 3, 6, 7, 9 and 10. The data signalling rates to be used are thoserecommended in Recommendation V.27ter, i.e. 4800 and 2400bit/s.Note 1: Some administrations pointed out that it would notbe possible to guarantee the service at a data signallingrate higher than 2400 bit/s.Note 2: It should be noted that there are equipments inservice using, inter alia, other modulation methods. The CCITT Draft Recommendation T.4 PAGE 12arrangement of interworking between equipment conforming toRecommendation T.4 and these existing equipments is subjectto further study.Note 3: For higher speed operation, such as may be possibleon leased circuits, it is provisionally agreed that Group 3apparatus may utilize the signals specifically defined in 1,2, 3, 4, 7, 8, 9, 11, and 12 of Recommendation V.29. ⌨️ 快捷键说明
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