WPCM 2%.B pz W"S^11>bbu"::Dg1:11bbbbbbbbbb11gggbuuuk1Xubuukuuuk111Rb:bbXbb1bb''X'bbbb:X1bXXXX;.;g:=::m:::mmmmm::::::mm:k1mubububububXubububub11111111bbbbbbbbbuXubbkbuXmmmmumububXXXXbububububbmbbbbbb:k:k::=kmmX:uXb'b:b:b:b'bmbbbb:::uXuXuXuXk:k:k:mbbbmbuXkXkXKQmmmm^b:kbbbbmbA@mmbmmbmmmmmmm:b:mmmbbmmmmmmmmmmmmXXmmmmmmmmmmmmmmmmmmcm`m`mm`m:mmmmmm}}}mjjmmmmmmmmmmmmmmm0mm}mmmmmmmmmmmmmmmmmmmmmmm}Mmmmmmmmmmmmmjmmmtmmmmmmmmm`'mmm`mmjmlWmmmmmmmmmmmmmmmmmmmW`mmmmjmM-lvetica#|x`H1`D4PkCQMS PS Jet Plus /800 II QPJPII.PRSPl`D4PkCg2W_ qr|xHelveticaCourier@ ,`H1`D4PkCmQrrr r  @C2K ` X` hp x (#%'H   x|@  3'3'Standard@8'@8'StandardC6QMS $=R- Recommendation R.103(R.1xy) <CODE AND SPEEDDEPENDANT TDM 600 BIT/S SYSTEM FOR USE IN <POINTTOPOINT OR BRANCHLINE MULDEX CONFIGURATIONS < HThe CCITT, considering  ` H H(a)  that telex subscribers are often geographically located in small groups; H(b)  that TDM multiplexing systems are economical for the transmission of large numbers of channels; H(c)  that certain telex switches handle TDM frames in accordance with SeriesR Recommendations directly and that frame fill should be optimized; H(d)  that telex switches handle channels at 50 bauds and a 7.5 unit code; H(e)  that a facility for regenerating startstop signals is used in new TELEX networks; H(f)  that the branchline multiplexing system should be capable of accepting and regenerating all the signals of the TELEX signalling system; H(g) that the minimum signal transfer delay through TDM systems is achieved by the transmission of interleaved elements; recommends Hthat, where branchline remote or low multiplex capacity TDM systems are to be used for telegraphy, the equipment shall comply with the following standards: 1. HSystem capacity HThe system shall be capable of multiplexing up to 8 channels at 50 bauds (7.5 bits including a stop element of 1.5 units). 2. HStartstop channel inputs  Hx 2.1 HThe modulation rate tolerance that shall be accepted on incoming 50 baud startstop signals with a stop element of 1.4 units shall be at least + 1.4%. 2.2 HWhen receiving characters at 50 bauds having nominally 1.5unit stop elements, the system shall be capable of transmitting without error isolated incoming characters that have a 1unit stop element, occurring at a maximum rate of one per second. 2.3HThe minimum interval between start elements of undistorted successive continuous characters that may be presented at the channel input when the nominal modulation rate is 50 bauds shall be 145 5/6 ms. 2.4HThere shall be no restriction on the continuous transmission of all characters (including combination No. 32 of International Telegraph AlphabetNo.2) when they are presented at the maximum permitted rate. 2.5HThe effective net margin on all channel inputs when undistorted signals are received from a transmitter having a nominal character length and rate shall be at least 40%. 2.6HAt the nominal modulation rate of 50 bauds, an input character start element shall be rejected if it is less than 0.4 units duration and shall be accepted if it is . more than 0.6 units duration. 2.7HElements corresponding to start polarity (at the distant multiplexer output) shall be inserted in the aggregate stream if the channels are unequipped. 2.8HIn the case of an opencircuit line condition at the startstop channel input, it shall be possible to choose to transmit elements corresponding to a steady start or stop polarity in the aggregate bit stream, according to the availability polarity selected. 3.HStartstop channel outputs 3.1HThe maximum degree of gross startstop distortion, produced by the system on a startstop channel, shall be 3% for all modulation rates. 3.2HThe maximum difference possible between the mean modulation rate of the channel output signals and the nominal modulation rate shall be 0.2%. 3.3HThe minimum stop element duration released at the output shall be 1.25units, whatever the distortion, the length of the stop element or the input rate within the range specified in 2.12.4 of this Recommendation of the character recognized at the other end, whether this character is in accordance with this Recommendation or RecommendationsR.101, R.102 or R.112 (for a rate of 50bauds and a 7.5unit code). 3.4HWithin 6 ms of the recognition of one of the failures described in 8.3 and 8.4 or carrier loss signalled by the modem, the steady polarity as selected in accordance with 2.8 shall be applied to the channel outputs of the TDM system affected. 3.5HThe affected terminal shall signal its synchronization status to the distant terminal over the signalling channel provided (control channel). 4.HMultiplexing details 4.1HChannel interleaving shall be on a bitbybit multiplexing basis. 4.2HBoth start and stop elements of each input character shall be transmitted through the aggregate. 4.3HThe transfer delay shall not exceed 60ms. 5.HFrame structure 5.1HA unique frame of 12bits, of duration 20ms, equivalent to an aggregate signal rate of 600bit/s shall be used, as shown in Table1/R.1xy: $TABLE 1/R.1xy * $Frame detailsă  .Ԍ 5.2HThe frame may be considered as a 600bit/s start/stop character, time slot "12" being the start element of polarity A, slots 10 and 11 forming the stop element of polarity Z, as shown in Figure1/R.1xy. #FIGURE 1/R.1xy * Branchline muldex frameă * * 6.HAggregate signal details 6.1HThe aggregate signal rate shall be 600bit/s. The tolerance on the modulation rate of the receive aggregate signals of the TDM system shall be between +2.3% and 0.5%. 6.2HThe effective net margin of the aggregate signal receiver of the TDM system shall be at least 40%. 6.3HThe maximum degree of isochronous distortion of the send aggregate signals of the TDM system shall be 5%. 6.4HWhen the TDM system is operated over an international telephonetype circuit, a modem complying with the appropriate aspects of the SeriesV Recommendations (in particular Recommendation V.23) should preferably be employed. 7.HControl channel encoding 7.1HThe 50bit/s control channel, the position of which in the frame described in 5 is accurately known, enables all risk of imitation to be eliminated. 7.2HThe structure of the control channel shall be in accordance with Figure2/R.1xy. It corresponds to an anisochronous character with a recurrence of 240ms, formed from a one unit start element of polarityZ, five information elements and a six unit stop element of polarityA.  .Ԍ #FIGURE 2/R.1.xy * Branchline muldex control channelă 7.3HThe control channel information provides for the transmission of information in accordance with Table2/R.1xy. $TABLE 2/R.1xy * Information transmitted by the control channelă Note The least significant bits are sent first. 8. HSynchronizing 8.1HThe maximum average synchronization time in the absence of error and imitation shall be 600 ms. 8.2HSynchronism shall be considered achieved after recognition of the frame positioning pattern (sequence of two elements of polarityZ followed by an element of polarityA) as described in 5 and at least two successive recognitions of the control channel (6 elements of polarityA followed by one element of polarityZ modulo12) in compliance with 7. 8.3HThe maximum time loss of sychronization due to a steady polarity signal shall be 120ms. .Ԍ 8.4HThe maximum time loss of synchronization for repeated error on the synchronization pattern in the control channel shall be 380 ms. 9.HTelex signalling 9.1HSpecifications for the signals used to establish, to clear and to control telex calls are laid down in Recommendation U.1 (types A and B), U.11 (typeC) and U.12 (typeD). RecommendationU.25 lists the modes of bothway telex signalling on a single circuit and the signalling combinations on a given aggregate that a TDM terminal shall be capable of handling. 9.2HRecommendation U.25 also lays down the tolerances on the control signals from a TDM terminal to telex and vice versa. 10.HMaintenance HThe branch looping facilities shall remain in accordance with RecommendationR.115. 11.HNumbering of channels HThe numbering of channels for the branch line telegraph muldex is given in Tables1/R.114 and 4/R.114 in accordance with the numbering scheme concerning RecommendationsR.101 and R.102. 12.HChannel selection HRemote channels shall be grouped so as to provide maximum ease of use of heterogeneous frames, a time slot allocation involving little variation in the sampling rate being retained. HThe selection of channel grouping and the method used shall be based on bilateral agreement, particularly when the channels of an existing system have to be branched without there being any possibility of a reconfiguration of the whole. HTables 3 and 4/R.1xy give an example of remote channel grouping on the basis of muldexes in conformity with RecommendationR.101 or R.102. $TABLE 3/R.1xy *  Example of grouping of remote channels for an R.101 muldexă   .Ԍ 1)HHAlthough incomplete, a sixth remote channel could be implemented with the remaining 50baud channels.`'H 2)HHChannel 0516 may not be remoted when the corresponding TS is used to transmit the maintenance channel in the R.101 multiplexer.`'H $TABLE 4/R.1xy *  Example of grouping of remote channels for an R.102 muldexă