WPCL 2BJ|x H   X  6p&6p&  HH Hp P X`h!(# X   Ё c4 P The text approved is: HP X`h!(# c4 P Fascicle VII.3 - Rec. T.4 Hp P X`h!(# c4 P 4.3h  Extended twodimensional coding scheme  H  The basic facsimile coding scheme specified in S 2.2 of Recommendation T.6 may be used as an option in Group 3 facsimile. This coding scheme is limited to the use of the Error Correction Mode specified in S3.3. 4.4h  Error limiting mode  H  Onedimensional coding scheme with the division of scan line into parts.  The onedimensional coding scheme with the division of scan line into parts is an optional extension of the onedimensional coding scheme specified in Annex B. 5X Modulation and demodulation  Group 3 apparatus operating on the general switched telephone network shall utilize the modulation, scambler, equalization and timing signals defined in Recommendation V.27 ter, specifically SS 2, 3, 7, 8, 9, 11 and theAppendix.  H 5.1  The training signal to be used shall be the long training sequence with protection against talker echo (see Recommendation V.27 ter, S 2.5.1, Table 3/V.27 ter). 5.2  The data signalling rates to be used are 4800 bit/s and 2400 bit/s as defined in Recommendation V.27 ter.  H  Note 1ĠISome Administrations pointed out that it would not be possible to guarantee the service at a data signalling rate higher than 2400 bit/s.  H  Note 2ĠIIt should be noted that there are equipments in service using, inter alia, other modulation methods.  H  Note 3ĠIWhere quality of communication service can successfully support higher speed operation, such as may be possible on leased circuits or highquality switched circuits. Group 3 apparatus may optionally utilize the modulation, scrambler, equalization and timing signals defined in Recommendations V.29, V.33 and V.17. For V.29 this specifically refers to SS 1, 2, 3, 4, 7, 8, 9, 10 and 11. Under this option the data should be nonmultiplexed and limited to the data signalling rates of 9600 bit/s and 7200 bit/s. For V.33 this specifically refers to SS 1, 2, 3, 4, 7 and8. Under this option the data should be nonmultiplexed. For V.17 this specifically refers to SS 1 through 5.  Note 4ĠIWhen V.33 signalling is used the training signal shall be preceded by a Talker Echo Protection signal. The Talker Echo Protection signal shall consist of an unmodulated carrier for a duration of 185 ms to 200 ms followed by a silent period of 20 to 25 ms.  H  Note 5ĠIWhen V.17 signalling is used the training signal shall include the Talker Echo Protection (TEP) signal defined in S 5.3/V.17. 6X Power at the transmitter output  The average power should be adjustable from I15 dBm to 0 dBm but the equipment should be so designed that there is no possibility of this adjustment being tampered with by an operator.  H  Note I The power levels over the international circuits will conform to Recommendation V.2.