Coming up: digital N.Z.

Press, 2 July 1983, Page 21

Coming up: digital N.Z.

By

NEILL BIRSS

The only non-digital company telephone exchanges, or PABXs, in Christchurch in 15 years are likely to be at Ferrymead or in the Canterbury Museum, if the telecommunications and business seminar held in Christchurch this week is any guide. The new digital PABX for most companies will be tucked inside a pastelshaded wall panel that looks like a heater, and the operator will control it from a console about the size of a pre-electric desk typewriter. The employer will be able to supply music which the Post Office will play through the exchange to soothe callers waiting on hold. The Post Office engineers took the businessmen and businesswomen at the conference into a world where the country’s telecommunications will be in an integrated, digital system, in which voice, telex, computer data, and signals from new communications devices are converted into numbers, and transmitted as pulses (the system is pulse code modulation). The change occurring in information technology was described as a “continuing explosion,” by Mr G. T. McPherson, engineer-in-chief of the Post Office. Simultaneous advances in four technologies are contributing to the development: ® Chip technology: Silicon chips have led to a reduction of 90 per cent in space occupied by the old electro-mechanical exchanges, and allowed the “intelligence” to be centred in software (programs) rather than in machinery, thus allowing much for flexibility for updating. Costs are falling with the chip technology. The processing speed is much faster, and there is better control. ® Digitisation: This is the conversion into figures of speech and other signals previously transmitted in waves. The numbers are groups of eight binary digits, and are transmitted in pulses. Development will be towards an “integrated services digital network” — that is, everything will be in digital form. ® Fibre optics: The higher the frequency of an electro-magnetic wave, the more information it can carry. A typical microwave has a wave-length of less than half a metre. Light has wave-lengths of about a tenth-of-a-million of a metre. The development of “pipes” of optical fibre and optical resources and receivers are now allowing the tapping of the vast information-carrying potential of light waves. ® Space technology: The positioning of satellites in geo-synchronus, or station-

The office and home phones of tomorrow. On the left is an “up-market” version that will be available to subscribers at a higher rental. Of the “Decorator” series, it will become available early next year, or as exchanges are converted to allow DTMF (dual-tone, multi-frequency) operation. When the handset is reversed in the cradle the conversation is broadcast to

the room. On the right is the “Pert” model, which will become the country’s standard phone. The Post Office is buying no more dial phones. When present stocks are exhausted, this push-button model will be the replacement. The buttons with asterisk and hash symbols are required to communicate with the new digital PABXs (company exchanges).

would have access to toll and international calls. This version could have piped music for those callers on hold.

A 250-extension exchange was being installed in Christchurch now, and a

500-line version is being developed. Features of these new digital company exchanges will include “automatic callback when free.” For more than 500 lines, the Post Office will obtain a system from Mitel, of Canada. This will cater for up to 10,000 extensions. The first systems are expected in 1984. Specialised systems can be made available, for places such as hospitals. Features include work stations that have a keyboard and a screen, as well as a phone. These are for communication with large internal databases. The packet-switching service, an impressive system for moving digital data, will be introduced next year, the conference was told. In this system, data will be divided into minute packets, including address information, and switched between stations in the main centres. The Post Office will provide links to users in smaller centres without any extra charge.

The conference was also told that with the introduction of the videotex in New Zealand, probably next year, a charge of 15c for each local call for transmitting data, would be instituted. And the timetable for the new communications? Mr K. Baird, a supervising engineer in Christchurch, said that by 1990 one or two fibre-optic' systems would probably be working in the Christchurch area. Some business subscribers could have a 64-kilobit service by 1985 if they wished. The fully integrated digital system for the country seemed

unlikely before 2001, but subscribers should be getting substantial benefits before the 19905. New digital exchanges are slowly being introduced into the Post Office network, marking a step towards the implementation of the digital network. These sophisticated exchanges provide user facilities such as a wake-up service, abbreviated dialling, hot-line service, and diversion of call to anywhere the user nominates. The Post Office will hold seminars on telecommunications and business in Timaru next Wednesday, and in Greymouth on August 3.