Letter-phone

Press, Volume CXI, Issue 32777, 30 November 1971, Page 21

Letter-phone

<n.z. Press Assn.—copyright) TOKYO 1 1 Japan has developed a telephone which combines the spoken and written word.

Experts at the research and development laboratory of Kokusai Denshin Denwa, the Japanese overseas communications authority, say that their new system can be used for international and domestic telephone calls. The letter-phone accepts handwritten letters as well as figures, making it invaluable for businessmen attempting to explain complicated procedures over a telephone. It would also remove the possibility of errors and misunderstandings inherent in purely oral transmissions, such as stock exchange transactions, the experts say. Oral and written transmissions can be handled simultaneously by dividing the wave-band now used for telephone circuits.

K.D.D. said that one half of the band, from 0.3 to 1.5 mega Hertz, would be used for voice, and the other half, from 1.5 to 2.7 mHz, for written messages.

The only limitation is that both parties cannot send letters at the same time.

The scientists say that they have succeeded in transmitting both character and voice signals with a clarity of about 91 per cent on a single circuit. The system is operated by a special ball-point pen containing a micro-switch that is activated as soon as pressure is applied by the pentip touching paper. The

movement of the pen is transmitted to a similar device at the receiving end that duplicates the moveme^D D said that a device known as Telemail had already been produced in the United States, to send only letters, but its system was the first in the world to use simultaneous voice and written transmissions. The letter-phone would cost 500,000 yen ($1240) a set to produce, but with mass production this may be brought down to 75,000 yen. The dual-purpose telephone may make its debut on the overseas service in two to three years, after further experimental use in Japan.