The picturephone® system: Line and trunk maintenance arrangements

New line and trunk maintenance arrangements have been developed for Picturephone® service. A switched method of accessing lines and trunks by means of the No. 5 crossbar system has been developed. In addition a new local test desk (LTD No. 15) and testboard (TB No. 23) have been made available. In this article we discuss these arrangements which represent another application of the switched access concept as an integral part of line and trunk maintenance arrangements.