F.—l

48

The percentages of the total wire-mileage in underground and aerial cables and open aerial wire respectively for the year ended 31st March, 1930, are as under : — Telephone-exchange wire in underground cables .. .. 68 per cent. Telephone-exchange wire in aerial cables .. .. 12 ~ Telephone-exchange open aerial wire .. .. . . .. 20 ~

Graph showing the Variation in Total Length of Wire in Underground and Aerial Cable, and Open Aerial Wire, 1921-30.

AUTOMATIC-TELEPHONE EXCHANGES. Christchurch Telephone Exchange : Conversion to Automatic Operation. The principal event in the development of automatic-telephone exchanges in New Zealand during the year was the conversion of the Christchurch Telephone Exchange to automatic working. The cut-over was carried out at midnight on Saturday, the 14th September, 1929. The conversion was accomplished with a minimum of trouble, and no faults developed beyond those usually associated with an operation of this nature. Since the cut-over the equipment has been working satisfactorily and is meeting all the demands made upon it. A large proportion of the apparatus at Christchurch is of the very latest and most improved type, the use of which will result in greater efficiency in operation and a minimum of maintenance. This is due to the fact that since the initial equipment for Christchurch was first engineered and ordered considerable development has taken place in automatic-telephone manufacture, and appreciable improvements have been made in the design of automatic equipment. Thus, while the telephone public of Christchurch had to wait somewhat longer than other large centres for their automatic telephones, they eventually received a system embodying the latest features. The Central Automatic-telephone Exchange is situated in Hereford Street. The main switchroom occupies the second floor of the building, and measures 85 ft. by 55 ft. At the time of the cut-over the switch-room contained equipment for 6,800 individual (or one party) lines, one group of 100 four-party lines to serve 400 subscribers, and two groups of 100 two-party lines to serve 400 subscribers. On the first floor is situated the toll-room, which contains an up-to-date toll-board, with ten operators' positions, equipped for 180 toll-lines, in addition to 450 rural subscribers' stations which are beyond the range of automatic dialling and which in consequence will be operated manually for the present.