In articles that mention RTTY codes there is usually reference to Baudot, Murray and ITA2 codes. These codes are often taken to be identical and interchangeable. For any two equipments to satisfactorily inter-operate, it is essential that the code in use is thoroughly specified and understood, and the same at each end. The purpose of this article is to explain the similarities, and the differences, between the codes, and to indicate their relationship to the Radio Amateur.
All codes have their strengths and their weaknesses.
For instance, one of the strengths of Morse code is that commonly used letters have short codes, making them easier to send. Whereas one of its weaknesses is the difference in length between the code for the shortest character 'E', and the code for the longest character '0', which takes 19 times as long to transmit. This vast difference in length made the Morse code difficult, but certainly not impossible, to mechanise. For example, the Creed Morse printer, developed in the early 1900s, read and printed in plain language, a perforated Morse tape at speeds of up to 100 words per minute. It had long been realised by many telegraphic engineers, that the real answer to the mechanisation of telegraphy was to use a code in which every character took the same time to transmit.