RTTY interface

EE September 1986 RTTY Some parts of the short-wave radio communications band are swarming with radio teletype (RTTY) signals from all over the world Although it is an offence under the Wireless Telegraphy Act 1949 to 1967 to intercept many of these transmissions, there are others, such as weather reports, amateur teletype messages, and public newscasts that may be received with impunity. The interface described in this article, in conjunction with a suitable RTTY software package, enables the received teletype message to be displayed on a computer monitor. Fig. I. The Baudot code is composed of 5 character bits, preceded and followed by a start and stop bit respectively. If you use a Junior Computer or DOS Junior, a suitable decoding pro- gramme was published in the June 1983 issue (RTTY Decoder, p. 30) of Elektor Electronics. That same issue contains a useful background to the reception of teletype signals (Morse and Radio Teletype, p. 52). EPROMs with RTTY decoding programmes a...