ITU-T R 72-1988 PERIODICITY OF MAINTENANCE MEASUREMENTS TO BE CARRIED OUT ON THE CHANNELS OF INTERNATIONAL VFT SYSTEMS《在国际音频电报系统的通路上进行维护测量的周期》.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 2 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(94%,%2!0(G0G042!.3-)33)/.0%2)/$)#)49G0G0/ amended at New Delhi, 1960and Geneva, 1964)The CCITT,consideringthat, for technical supervision of operations, maintenance measurements on international voice

2、frequencytelegraph (VFT) channels are necessary,unanimously declares the view(1) that maintenance measurements be carried out on international VFT channels once every three months(once every six months for 50-baud channels spaced at 240 Hz conforming to Recommendation R.35 bis);(2) that there is no need to carry out measurements more frequently on channels making up long circuits orcircuits used in a switched network;(3) that, when it is observed that the number of maladjustments is too high, supplementary measurementsshould be performed by agreement between the Administrations concerned.