TELEGRAPHIC SERVICE

Grey River Argus, 28 May 1935, Page 7

TELEGRAPHIC SERVICE

Speeding up Transmission THE TELEPRINTER AT WORK. Several months ago a cable from England indicated that the last Morse telegraph message had been sent in Great Britain. Automatic methods of transmitting have replaced the old hand method. A similar development has been going on for some years in New Zealand and will be accelerated shortly by the introduction of the teleprinter at a number of additional offices. The main centres of the Dominion are linked up by the Multiplexsystem, which provides over one line four sending channels in each directum simultaneously, making a total of eight channels. The introduction of mach-ine-printing telegraphic systems has had a very important bearing in keeping down the capital cost of the tele graph service. If no such system as the Multiplex had been available in 1921, the increasing volume of traffic between the North and South Is’ands would have made it necessary at that date to lay two more cables across Cook Strait, and similar conditions would have necessitated greater capital expenditure on long distance land lines. For communication between centres where the volume of traffic does not demand the great capacity of the Multiplex, the Post Office is gradually extending the use of the Creed teleprinter. a British instrument. To transmit messages by the teleprinter, the message is first typed on a standard typewriter keyboard, which causes a transmitting tape to be perforated with certain combinations of holes —a different combination for each letter. The code used is not the ordinary morse code of dots and dashes, but is what is known as the five-unit code. Each letter is five units in length. From the keyboard the tape feeds into the transmitter, and the combination of holes for a particular letter causes a corresponding combination of negative and positive impulses to be sent over the line.

At the distant station, these impulses cause the magnet in the printer to be operated in a certain sequence—a different sequence for each letter —am! from any particular sequence the required letter is printed on the tape. The tape is then cut. off and gummed to the telegram form for forwarding to the addressee.

The average working speed of Morse transmission is about 25 words per minute, but by the teleprinter 66 words per minute can be transmitted in each direction, thus greatly facilitating the handling of traffic. It has also been definitely established that there is an appreciable improvement in accuracy through the use of automatic transmission. Still another advantage, particularly where telegraph traffic is only intermittent, is that while the use of the Morse necessitates an oper-

ator at the receiving end. al! that is necessary with the teleprinter is for the apparatus to be running, when the message is automatically printed. There is no necessity, for instance, to wait until a telegraphist is freed from another circuit before telegrams intended for his office can be received. They will come through and be typed out on the machine while he is attending to other business.

The small number of teleprinters already in use have proved their suit ability for New Zealand requirements, and it is proposed to provide them on 21 other circuits. When the plan is complete, there will be teleprinter channels from Auckland to Whangarei. Thames, Rotorua and Hamilton. From Wellington there are already teleprinter channels to Gisborne, Hastings, Palmerston North and additional ones will go to Stratford, Hawera, Marton, Palmerston North, Dannevirke, Masterton, Nelson and Blenheim. From Christchurch there will be teleprinter channels to Westport, Greymouth, Ashburton, Timaru (two). Oamaru, and Invercargill, while Dunedin will have teleprinter outlets to Gore and Invercargill.