A NEW LINK

Dominion, Volume 19, Issue 99, 21 January 1926, Page 6

A NEW LINK

BETWEEN NORTH AND SOUTH ISLANDS

TELEPHONE CABLE BEING MANUFACTURED

The Post and Telegraph Department has been advised chat the new telephonic cable that is being manufactured by Sietnanns, Ltd., of for Cook Strait, is likely to be shipped from London about the end of the present month, and should arrive here about the middle of March. This cable —about* forty miles in length—will be the first of its kind in New Zealand, and will enable practically any telephone subscriber in the North Island to be put in conversation with any subscriber in the South Island.

The nature of a telephonic cable differs considerably from that of the ordinary telegraphic cable of commerce in that the “loading” is differently applied. This loading is necessary for technical reasons in long lengths of telephonic cable, and may be applied in two ways, either by the insertion here and there of copper coils during the manufacture of the cable (coils which become part and parcel of the cable itself). or by closely wrapping the copper conductor of the cable with an alloy of iron and nickel in strip form. The coil method of “loading” is rather delicate, and cables so loaded have necessarily to be handled very carefully, because when the coils become damaged in any way it is a more difficult matter to locate the damaged point than in the case of a mishap to a telegraphic cable. So as Cook Strait is rather turbulent water, with a most irregular floor, the coil method of “loading” was abandoned in favour of the "wrapped” cable.

It was announced by a cablegram in The dominion this week that the Eastern Extension Company was laying a new cable between Cocos Island and Fremantle, and reference was made in that article to it being a continuously loaded cable. That is something akin to the new telephonic •cable for Cook Strait, though the “loading” for telegraphic signalling is a different problem to that for the conduct of human speech.