In-flight Phone Calls Are Almost Here

In-flight Phone Calls Are Almost Here

Sydney Morning Herald

Monday November 26, 1990

By TONY SARNO

QANTAS plans to introduce in-flight telephones for passengers, and data communications for aircrew, on the next jumbo to be delivered to the airline.

It is expected that after some testing, by the end of 1991, passengers on this and subsequent planes will be able to hire telephone handsets with their credit cards, take them back to their seats, and call home or the office from 40,000feet anywhere in the world, except over the polar regions.

Initially, the phones, based on a new satellite communications network, will be used by Qantas aircrew. The system will also transmit faxes, and low-speed computer data from monitors of the aircraft's performance, as well as an automatic tracking signal to help air traffic control.

The first of the four satellites which will make all this possible has just been launched by the Inmarsat international satellite operator. Australia's OTC is a member of Inmarsat, as are 61 other major telecommunications carriers.

Qantas told the Herald last week that it plans to take advantage of the new Inmarsat-2 satellites by outfitting its next 747-400, to be delivered by Boeing next month, with a special "high gain" satellite communications antenna.

While in-flight passenger phone services are available on some US airlines flying over US territory, these link into a network of specialised transmitters on the ground, rather than into satellites. As a result, their coverage is not global, and they are subject to interference and occasional losses of contact.

In-flight calling has not been possible for passengers in Australian skies because we do not have such a communications grid on the ground. The only contact between aircraft and ground has taken place via the more limited HF radio frequency, on which the OTC SkyCom service, available only for aircrew, is based.

The Inmarsat-2 satellites will permit global communications with hardly any of the interference experienced by other systems. The only areas outside their reach will be the North Pole and Antarctica.

The first Inmarsat-2 satellite was launched from Cape Canaveral, Florida, on October 30, and is now in geostationary orbit over the Indian Ocean, having its systems tested. Phone calls with Australia as a destination will reach the satellite from flying aircraft, and will subsequently be re-routed to the Australian land-based telephone network via OTC's new ground station at Ngangara , 20km north of Perth.

Qantas is one of the first clients signed by a marketing consortium selling the Inmarsat-Aero in-flight phone facility.

This includes OTC, as well as France Telecom, Teleglobe Canada, and SITA (a communications company with just about every world airline as a member).

In addition to Qantas, Cathay Pacific, Finnair, Swissair and China Airlines have also signed to eventually make available passenger voice communications from the air.

Mr Don Koulaouzos , marketing manager, mobile satellite services, at OTC, told the Herald that the in-flight passenger phones would probably be placed somewhere on the bulkheads in the aircraft cabin.

Use of a phone would be charged to credit cards, which would be left in a special slot while the passenger used the phone, to ensure that the handset was returned.

While the Qantas crew will be able to transmit and receive low-speed computer data, the phone service that will be available to passengers, however, will not be capable of carrying computer communications, unlike ordinary phones on the ground.

This is because, according to Mr Koulaouzos, the Inmarsat-Aero service uses a special digital method of sending voice, called linear predictive coding. The voice is initially compressed by a computer, and then only samples of it sent to the receiving station. There, a computer uses special algorithms to fill in the missing bits, and reconstruct the voice as it should sound.

Mr Koulaouzos said: "The computer predicts what the gaps or holes in the voice are. It's very difficult to tell the difference between that and a voice on a normal telephone.

"The other benefit of the system is that it's designed to recognise human speech, not sound, so it has inherent background noise suppression."

The reason that linear predictive coding is used is that it dramatically reduces the bandwidth and power needed for the voice to be transmitted when compared to a standard voice call being transmitted by the Intelsat land-based satellite network.

Mr Koulaouzos predicts a huge demand for the in-flight phones, and believes they will eventually come to be regarded as a normal part of air travel.

Travellers will use them to conduct business and end the isolation-cell atmosphere of many long, intercontinental flights, he says, or to ring ahead to let the family or friends know whether their plane will arrive on time.