Britain’s Telephone System.

Hokitika Guardian, 22 June 1922, Page 4

Britain’s Telephone System.

(.In April 28th the “Manchester Gnaidinii” published a chart of Engl.inJ showing the complete national system of underground cables contemplated b) the Rest Office. The system involves a . network radiating from London to Mar- . gate, Ramsgate and Dover, Brightun, , Portsmouth, and Southampton, through j Bristol to Plymouth and Penzance, ' from Gloucester through Cardiff andSwansea, and luutaw.rd to Xoiwich Liverpool, Manchester, Leeds, Hull, anil north-east const ports and on to Edinburgh, Gasgow and Kirkcaldy. ; j The only cable actually in use is that; between Lardn and .Manchester, which was opened for service i n April 27th. ; Until then telephonic eointnuinoati: li , between Manchester and London w-'R j conducted through twenty one i,\er-*cad . line circuits. The greatest and most obvious drawback to an aerial system of telephonic eominu’.iication is its liability to interruption by even moderate sturnis or to complete breakdown in a heavy gale. But an underground cable that would answer every bit as well as an overhead line was not an engineering possibility until the the - mionie valve, which has already so profoundly influenced wireless te’e-gi-aph.v, was applied experimentally ami with wonderfully sueeesslul results to the telephone. But simply, the effect of ti(o thermionic valve as applied to the 180 miles of cable between Manchester and Ror.it ui is to amplify the sound cui i i nis so tinny times that the

voice nf a parson /peaking flora Loniliin call ha heard as distinctly m Manchester a>. if I,ll* > e • n were speaking from Dili- a iy. Hilt t!ie ■ -. li e- 'if lie icucd ei;irit;.- and, v ! ■ e , ! ■ ml ami immunity inn aPi pan in vagaries are mil tlio only mlvantng'-s. Those insults are g 1 by o-ing eahle containing infinitely less heavy conductors than these employed in oveiliead lines. The eonduetors as d for overhead lines often weigh ns nn "i a a 8001 b to the mile. Tn the no tv eahle the conductors do not weigh mote than 401 b which means a very great ecoainy. The thermionic valve, which i< th" fun lamentnl thing in the new syslmn. works flirt ugh ‘•'re] oaten ” ‘■■l at ions, which, in :i perfected rv-'tem, \vt•.ll l li he placed at intervals roughly of 00 miles along the • cable.