Facsimile Interface For Atari St

FE, ,1989 FACSIMILE INTERFACE FOR ATARI ST by P. Neufeld DB9JG Are you interested in receiving weather charts and press photographs from all over the world? Here is a simple-to-build interface that works in conjunction with an Atari ST computer running a GFA-BASIC program. Radio facsimile transmissions are fairly simple to decode and convert to legible documents. The information trans- mitted is composed of picture elements (pixels), whose relative intensity on the black-to-white scale is recorded and translated in frequency. Most facsimile systems based on electromechanical ap- paratus work with a centre frequency of 1900 Hz, while maximum white and black correspond to frequency shifts of + 400 Hz and -400 Hz respectively. All-electronic facsimile systems use other centre freqencies and shifts, e.g., ±2400 Hz and ±1600 Hz. In the modernized fax system, synchronization of the picture at the receiver side is achieved with start and stop tones, which are frequency-modulated on t...