ÿWPCL ûÿ2BJ|xÐ ` ÐÐÌÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿH øÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÌÐÐ °°°è ÐÑ Âx„|ü@Ž ÑÐ Å°6Ø'°6Ø'Å Ð13.ÁHÁÓÓÃÃRecommendation G.772ÄÄ Áà0ÁDIGITAL PROTECTED MONITORING POINTSƒ Ð h ÐÃÃNoteÄÄ © The detailed requirements contained in this Recommendation are applicable to the 2048 kbit/s hierarchy. The application of the principles defined in this Recommendation to the 1544 kbit/s hierarchy is for further study. 1.ÁHÁÃÃDefinitionÄÄ ÁHÁA protected monitoring point provides a digital interface at which it is possible to monitor the transmitted signal and to make measurements with suitable test equipments [1]. 2.ÁHÁÃÃLocationÄÄ ÁHÁThe possible locations for protected monitoring points can be: ÁHÁa)Âh   Âat the output ports of an equipment,ÆÆ ÁHÁb)Âh   Âin the signal path between equipments.ÆÆ ÁHÁSome examples are shown in Figure 1. 3.ÁHÁÃÃElectrical characteristics of the protected monitoring pointÄÄ ÃÃNoteÄÄ © The reference for all parameters associated with protected monitoring points shall be the relevant output interface as defined in Recommendation G.703. (See Figures 1 and 2.) 3.1ÁHÁÃÃImpedanceÄÄ ÁHÁThe load impedance presented by the test equipment at the protected monitoring point is the nominal impedance for the corresponding transmission path interface as defined in Recommendation G.703. 3.2ÁHÁÃÃAttenuationÄÄ ÁHÁThe attenuation between the transmission path interface and the protected monitoring point, when the impedance presented by the test and measuring equipment connected to the protected monitoring point is equal to the nominal impedance for the relevant interface as defined in Recommendation G.703, shall be A ÃÃ+ÄÄ 1 dB for all frequencies in the range 2.5% to 150% of the nominal bit rate at the interface. ÁHÁDifferent values may be necessary at different nominal bit rates. ÁHÁThe value of A is under study. ÁHÁThe digital signal level presented at the transmission path interface of the protected monitoring point shall be as defined in Recommendation G.703 but modified by the characteristics of the interconnecting cable. The attenuation of the cable shall be assumed to follow a ÀÀf loss and the loss X at a frequency equal to both the nominal bit rate is given below: ÁHÁ0 ÃÃ<ÄÄ X ÃÃ<ÄÄ 3 dB for 64 kbit/s ÁHÁ0 ÃÃ<ÄÄ X ÃÃ<ÄÄ 6 dB for 2 and 8 Mbit/s ÁHÁ0 ÃÃ<ÄÄ X ÃÃ<ÄÄ 12 dB for 34 and 140 Mbit/s ÃÃNoteÄÄ © For a protected monitoring point device at an equipment output port, as described in Figure 1a, the value of X is 0 dB. 3.3ÁHÁÃÃProtection of the PMP deviceÄÄ 3.3.1ÁHÁThe protection of the protected monitoring point device against electrostatic discharges shall accord with the requirements of CCITT Recommendation K.y [3] and IEC Publication 801.2 [4]. 3.3.2ÁHÁNo damage shall result from the application of any load impedance, including short and open circuits, to the protected monitoring point. 3.3.3ÁHÁThe protection against the inadvertent application of voltages to the protected monitoring point is under study. 4.ÁHÁÃÃElectrical characteristics of the transmission path interfaceÄÄ ÃÃNoteÄÄ © The reference for all parameters associated with the transmission path interface shall be the relevant output interface as defined in Recommendation G.703. 4.1ÁHÁÃÃImpedanceÄÄ ÁHÁThe transmission path interface shall have the nominal impedance as defined in Recommendation G.703 for the relevant bit rate output interface. 4.2ÁHÁÃÃReturn lossÄÄ ÁHÁWith the transmission path interface terminated with its nominal impedance, the return loss shall comply with the requirements defined in Recommendation G.703 for the relevant bit rate output interface. This shall apply with any value of load impedance, including short and open circuits, applied to the protected monitoring point. 4.3ÁHÁÃÃAttenuationÄÄ ÁHÁThe attenuation in the transmission path, when the transmission path interface is terminated in its nominal impedance, shall be less than Y dB (see Figure 2) for all frequencies in the range 2.5% to 150% of the nominal bit rate, when the protected monitoring point is terminated in any load impedance, including short and open circuit. ÁHÁThe value of Y is for further study, 1 dB has already been proposed. 4.4ÁHÁÃÃImpact of the protected monitoring point on the maximum cable lengthÄÄ ÁHÁThe introduction of a protected monitoring point as described in Figure 1b with an attenuation of Y dB will effectively reduce the maximum attenuation allowed for in Recommendation G.703 by Y dB. 4.5ÁHÁÃÃProtection of the transmitted signalÄÄ ÁHÁUnder study. ÁHÁThe degree of protection shall be specified in terms of an X% variation in the pulse mask of the signal on the transmission path when the protected monitoring point is terminated in any impedance including short and open circuit. Ô ñ,ÔŒ Áà8NÁFIGURE 2ƒ Áà8RÁƒ Áà8FÁÃÃDefinition of A, X and YÄă Áà8MÁÃÃREFERENCESÄă Áà8RÁƒ ÐÌÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿàH øÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÌÐ1.ÂðàÂCCITT Recommendation "Maintenance terminology and definitions", Vol. IV, Recommendation M.60.ÆÆ 2.ÂðàÂCCITT Recommendation "Physical/electrical characteristics of hierarchical digital interfaces", Vol. III, Recommendation G.703.ÆÆ 3.ÂðàÂCCITT Recommendation "Resistability of subscribers terminals to overvoltages and overcurrents", Vol. IX, Recommendation K.y.ÆÆ 4.ÂðàÂIEC Publication, "Prescriptions relatives aux dÀ)Àcharges À)Àlectrostatiques", Publication 801©2.ÆÆ ÐÌÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿH øÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÌÐ 14.ÁHÁÃÃSupplement No. 32ÄÄ Áà8=ÁÃÃTransfer of alarm information on 60©channelÄă Áà8EÁÃÃtransmultiplexing equipmentÄă Áà8RÁƒ Áà87Á(Melbourne, 1988; referred to in Recommendation G.793)ƒ ÁHÁThe text of this Supplement has not been included in the final report, but will be printed in the Blue Book at the appropriate place. 15.ÂàHÂÃÃSupplement No. 33ÄÄÆÆ Áà8AÁÃÃExample of fibre design guidelinesÄă Áà86Á(diagrams used in Japan and the United Kingdom, referredƒ Áà8?Áto in Recommendations G.652 and G.634)ƒ ÁHÁThe text of this Supplement has not been included in the final report, but will be printed in the Blue Book at the appropriate place. 16.ÂàHÂÃÃSupplement No. 34ÄÄÆÆ Áà8@ÁÃÃTemperature in underground containersÄă Áà8BÁÃÃfor the installation of repeatersÄă Áà8@Á(referred to in Recommendation G.950)ƒ ÁHÁThe text of this Supplement has not been included in the final report, but will be printed in the Blue Book at the appropriate place. Áà8RÁÃà        Äă