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CONVERSION TO AUTOMATIC WORKING OF WHANGAREI TELEPHONE EXCHANGE. During the year a commencement was made with the work of installing automatic telephoneexchange switching-apparatus at Whangarei. Excellent progress has been made with the work ; and it is expected that the change-over to automatic working will take place at an early date. The equipment that is being installed at "Whangarei consists of 1,100 subscribers' lines, and is similar to that provided at Marton. Conversion to Automatic Working of Lower Hutt Telephone Exchange. Good progress has been made with the work of installing the new automatic switching-equipment at Lower Hutt. In October the new exchange building, which occupies a site'at the corner of Laing's and Knight's Roads, was completed and handed over to the Department, and a commencement was made immediately with the preliminary work necessary in connection with the installation of the automatic switching-apparatus. Owing to the relative geographical position of the Lower Hutt tele-phone-exchange area to the Wellington metropolitan-exchange area, and to the social relationship existing between telephone subscribers in the two areas, it has been necessary to incorporate in the new system certain features not hitherto necessary in plants purchased for installation in the Dominion. Details of the equipment were given in the report for 1929-30. No difficulty is being experienced with the installation of the plant, which is being undertaken by the Department's technical staff. It is expected that the conversion to automatic working at Lower Hutt will take place within the next few months. Rural Automatic Telephone Exchanges. A rural automatic telephone-exchange unit was installed at Heretaunga in November. In addition to the general suitability of the area for the purpose, the decision to install such a unit at Heretaunga was influenced by three major considerations —namely, the existence of ample accommodation in the post-office building, the desirability of having the unit installed in close proximity to a large automaticexchange area, thereby enabling a close watch to be kept on its operation, and the avoidance of expenditure in the carrying-out of expensive cabling work which would otherwise have been necessary between Heretaunga and Upper Hutt. The unit is functioning perfectly, and is meeting all the demands made upon it. The performance of the equipment will be observed, with a view to determining the extent to which this class of apparatus is capable of meeting certain telephone conditions in the Dominion. Private-branch Exchanges. Twenty-one private-branch exchange installations, accommodating a total of 122 trunk and 786 extension lines, were brought into service during the year. The demand for this type of service, especially from business houses, is well maintained, but, unfortunately, the existing financial position renders it necessary to defer for the time being the purchase and installation of the additional units necessary to meet the demand. GENERAL ENGINEERING. Duct Splicing of Underground Telephone Cables. In the past years the economical utilization of remnants or recovered lengths of the larger-sized underground cables has presented a difficult problem, as the standard size of duct used will not accommodate the comparatively large-sized joints which have hitherto been made on such cables, and recovered pieces were frequently unsuitable in length for use in new duct sections. A search for a means of utilizing these odd lengths was made by the Department's Laboratory. The result has been a new type ot joint of such reduced size that joined cables of the largest size used by the Departmentcan be drawn into the ducts. The principle of the new type of joint is to extend the length and to reduce the diameter by " staggering " the joints of the individual wires. Owing to the longer lead sleeves required in such cases, and the fact that the joint requires to be strong-enough to withstand the stresses involved when being drawn into the duct, the usual method of attaching the sleeve by means of plumbers' wiped joints was unsuitable, and lead burning had to be resorted to. The method adopted has now been fully tested in practice, and has been found to be eminently satisfactory. As a result, short lengths of cable, many of which previously possessed only a scrap value, can be economically made up to any required length and brought into use at their full value. In addition to the economies that will result from time to time, the present financial position of the Department was eased by deferring the ordering of a large quantity of cable, to the value of £1,500, that was required for immediate use. So far as the Department is aware, this method has not previously been used by any other Administration in connection with telephone cables. Telephone-exchange Power Plant. With the greater reliability of the electric-power supply in the various exchange areas in New Zealand, it has been found possible, by operating exchanges as far as possible directly from the electric mains, to improve the power-supply arrangements in many exchanges, and so minimize the size of batteries required for reserve purposes and increase the life of existing batteries. With this in view, much greater use has been made of supplementary A.C.-D.C. conversion equipment such as rectifiers ; and it has been found possible during periods when the exchange is unattended to relieve the load on the exchange battery by the use of such equipment. It is expected that this policy will result in

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