The "on" state was referred to as the "mark" state, and the "off" condition was called the "space" state.
When a key was pressed, the teletype machine would generate a series of pulses by switching a DC voltage on or off. (click picture above for a larger view)įrom the late nineteenth century, the standard coding system for teleprinters was the 5-unit Baudot code (named after its inventor, Emile Baudot). These machines were capable of sending data at a much faster rate than was possible using Morse, and messages could be printed out automatically at the receiving end. For printing, teletype machines used a motor-driven mechanism that controlled a printing head or a set of typehammers like those used in ordinary typewriters. The original teleprinters included a keyboard that could generate a series of electrical impulses corresponding to whichever key was typed. This required a qualified Morse operator at each end of the circuit, and the data rate was slow because the speed was limited by the ability of the operators to copy Morse signals by ear. Before that time, all telegraph communications had used Morse Code.
Teleprinter machines were first used for landline communication in the mid nineteenth century.
RTTY (short for RadioTeleTYpe) is the first digital mode to be used by radio amateurs.
0 kommentar(er)
