TELEGRAPH EXTENSIONS

Evening Star, Issue 20315, 25 October 1929, Page 6

TELEGRAPH EXTENSIONS

IMPORTANT DEVELOPMENTS CARRIER CURRENT TELEPHONY The expenditure for the last financial year in extending and improving the telephone, telegraph, and wireless facilities throughout the dominion amounted to £624,414. Of tho works upon which capital expenditure was incurred -during the year the following were the more important Tho installation of two carrier-current telephone channels between Auckland and Hamilton; tho erection of new metallic circuits between Palmerston North and Wanganui, To Aroha and Hamilton, Rotorua and Atiamuri, Gisborne and Morere, Carterton and Greytown, Blenheim and Seddon, Darfield and Coalgate, Christchurch and Leeston, llaugiora and Oxford, Tokarahi and, Duntroon; the laying of a submarine cable between Maraetai and Awaroa; the installation of direct-dialling, circuits between Wellington and Blenheim, Wellington and Masterton, Paekakariki ana Wellington, and Palmerston North and Dannevirke, and the improvement and extension 'generally of toll facilities; the installation of a universal battery system in Palmerston North Telegraph Office; the opening of new exchanges at Wellsford, Towai, Waimamaku, Mangapai, Xirikopuni, and Tokanui; tho installation in 37 exchanges of additional switching equipment for 3,940 exclusive lines and 200 party lines; the establishment of 66 new pubic call offices (coin-in-the-slot telephones); the laying of 2,772 chains of underground telephone ducts and 10,160 chains of underground cable; the erection of 5,260 chains of overhead cable; tho erection of 850 miles of pole lino and 8,270 miles of open wire; and the connection of 12,119 new’ subscribers’ stations. Some idea of the extensive network of linos interconnecting tho various exchanges and telegraph offices throughout tho dominion may be gauged from the fact that on March 31 last there wore approximately 380,000 poles in use, carrying over 62,602 miles of open wire. In addition, approximately 400,000 poles and over 495,000 miles of wire of all classes were in existence in telephone exchange subscribers’ lines. Notwithstanding the many important extensions that have been made to the system of electrical communications during the last few years, the necessity for additional facilities, particularly in tho matter of telephone lines, is just as real and just as urgent to-day as it was ten years ago. This condition is not peculiar to New Zealand; it is world-wido. Tn all tho foremost telephone countries the difficulty is not to obtain the traffic, but to keep pace with it in the matter of providing additional circuits. Telephone service is now so intimately connected with the business aud social life of the community that, uo sooner is telephone communication provided between cities and towns widely separated (and not previously interconnected) than there is a demand for additional circuits to relieve the traffic congestion. A striking example in that respect is the interisland telephone service. Two years ago telephonic communication between Wellington and Christchurch was impossible To-day, as a result of providing an efficient means of communication between the two cities, it is necessary to double the capacity of the South Island landline section of the Wellington-Christ-church circuit in order to relieve the congestion of traffic. LONG-DISTANCE FACILITIES. In the matter of extending and improving the long-distance telephone facilities throughout tho dominion the most important development during the year was the introduction of the system known as carrier-current telephony. The carrier-current system consists, briefly, in the application of radiofrequency methods to existing telephone circuits, thus enabling additional telephone speech channels to be obtained without increasing the existing wives. The new process is in reality a system of wireless communication, in which the electro-magnctic waves, instead of being broadcast, are directed along the metallic conductors of the wires already erected without interfering with the purposes for which such wires were originally designed. The most important feature of the new system from the practical point of vjew is the large saving it effects in installation and line maintenance costs. In addition, the system provides an excellent speaking circuit, and as compared with the wellknown metallic wire circuit it gives louder speech and is less subject to the interfering noises caused by power lines and similar disturbing influences. The initial installation in New Zealand ol carrier-current equipment comprises three single-channel systems for use between Auckland and Hamilton; a three-channel system (or use between Hamilton and Palmerston North, which will provide a single channel between Hamilton and Palmerston North and two channels between Wellington and Auckland; and a single-channel system to supplement the South Island landline section of the Wellington-Christ-church telephone circuit. At the present time two channels of tho Auck-land-Hamilton system are in operation, and it is hoped to have the other systems working at an early date. When the three system mentioned are in use and the equipment is properly tuned in high-grade and efficient telephone speech channels will be available at any hour of the day or night between Auckland and Dunedin and between tho principal _ centres within those limits. In addition, ranch of the congestion which now exists on the long-distance lines within each of the two islands will be considerably relieved. As soon as the above-mentioned systems are in operation consideration will be given to tho question of installing carrier systems between other centres. A great deal of work was also carried out during the year in the direction of extending and improving the facilities for short-haul traffic. In almost every part of the dominion some, facility was provided for the purpose of relieving congestion of traffic or for giving service to some backblocks settlers that had not previously enjoyed any of the privileges or conveniences of the telephone. In addition, tho speech efficiency oi toil circuits and the physical condition of the lines were considerably improved by the carrying out of many reconstruction works. These works included the renewal of pole lines, the replacing or respacing of poles, the strengtuening of existing poles, the regulation of wires, the rearranging of transpositions, the substitution of copper for iron wires, and the re-erectioai of circuits on the twist system. LOCAL EXCHANGE SYSTEM. The steady expansion and growth of the local exchange systems which has characterised telephone development in

New Zealand during recent years was continued during 1928, tho number of new connections installed being 12,119, as compared with am average of 12,112 per year during the preceding five years. The total number of telephone connections with departmental exchanges at March 31 was 147,936, tho number of telephones connected with toll stations and non-departmental stations 4,605, making a total of 152,541, which represents over ten telephones per 100 of the population, a telephone density exceeded only by the United States and Canada. A feature of last year’s development in telephone exchaaige systems was tho large number of intercommunicating and extension telephones installed, the rate of increase being 7.7 per cent., as compared with 4.9 per cent, in the case of main stations. This was due to a large extent to the increased number of_ intercommunicating systems installed in business houses The local intercommunicating system in most popular demand was the key box interphone type, large numbers of which were installed im business establishments where the requirements in intercommunicating facilities did not exceed twenty positions. Next in order of demand were private branch exchanges of tho full automatic type with capacities varying from twenty extension stations upwards. The latest devefdpment in the automatic telephone industry is the manufacture of a small type of automatic exchange suitable for rural communities and capable of giving a twenty-four-hour service. One of such systems has been obtained by the department and will shortly be m a suitable rural locality with a view to testing out its suitability in actual practice for the exacting conditions that prevail in rural exchange areas in New Zealand, and where a twenty-four-hour service under manual conditions would bo economically prohibitive. Should the trial prove successful and the actual costs be reasonably low, tho question of installing twenty-four-hour service automatic exchanges in rural communities will be fully investigated. For economic reasons, however, the development of such a policy would have to proceed gradually, as a large capital expenditure would be involved. Tho Christchurch Telephone Exchange, to which over 11,000 stations are connected, is one of the largest in New Zealand to be converted to full automatic operation, and will increase by approximately 14 per cant, the number of automatic telephones in use in tho dominion. The conversion to automatic working would have taken place many months ago had not there been some unfortunate delays in the delivery of the equipment. Notwithstanding these delays, however, the actual time occupied m the work of installation compares favourably with that for similar exchanges of like capacity in this and other countries where machine switching methods have been introduced. With practically all the essential equipment now in sight an intensive effort is being made to hasten completion of the work, additional skilled labour from other parts of the dominion having been concentrated at Christchurch to assist in the construction of the internal switching system, as well as in the installation of subscribers’ telephones and subsidiary apparatus. If the outstanding items of equipment for subscribers’ stations come to hand according to schedule time, as is confidently expected, the whole of the Christchurch metropolitan area will ba completed and converted to automatic working in a few months. One indirect advantage arising from the delay that has occurred is that the Christchurch area, being the last of the large centres to erceive full automatic treatment, will have the benefit of a number of the very latest developments in machine switching equipment. As soon as the cut-over takes place attention will be directed to the installation of a further 2,000-line extension, so that no unnecessary delay will arise in meeting the growth that is expected to follow the introduction of automatic methods.