THE LAST LINK

Hokitika Guardian, 15 November 1930, Page 7

THE LAST LINK

CARRIER TELEPHONY. SPEECH OF EXCELLENT CL A HIT'S WELLINGTON, November 11. Only last week the carrier system of telephony was opened np commercially between Invercargill and Dunedin, thus completinrg the last link between Auckland and Invercargill. On that day—Monday to be correct —the mayor of Invercargill spoke with the town clerk ; of Auckland, and the speech could not have been clearer had they been at either end of Dee Street. The mayor of Invercargill was immensely impressed with the new service, and said he liked it all the more as, being a Scotsman, the talk was free.

The completion of this last link is an important achievement in the latest order of telephony. Hitherto it has been possible to obtain communication by speech over the ordinary telegraph wires, a service which has answered more or less satisfactorily, but to-day the whole of the main lines and chief towns of New Zealand are linked up telephonic-ally by what is known as the "carrier’ ’ system, which gives perfect results ;

Tile carrier system involves the use of radio frequency impulses as an adjunct to the ordinary telephone toll wire, permitting of a number of conversations being carried on at the same time, without increasing the number of wires. Hitherto only one conversation could be held over a telegraph wire at a time, hut by creating a bypass line (operated by equipment similar to that used in a small radio broadcast set) it has been found possible to create channels of connection on the ono wire only, so that instead of only one conversation being possible at a time, four separate and distinct conversations can be held without any confusion. It is wired wireless.

Another feature, and a very, imprrtant one, is that while broadcast messages radiate in all directions equally from the station, the message sent per carrier system is just as scent as the ordinary telephone conversnti >n, ns fhe talk only travels per medium of the wire, but in nigh frequency impulses. The new system is better than anything yet used for long distance conversation because of its economy in power, its directivity, and its secrecy.-Rhe initial cost of the system is fairly high, as at each end of'each section there has to be. transmitting and receiving equipment.