RY (test signal)
Encyclopedia
RYRYRYRY... is a character string that was widely used to test a five-level teleprinter
or RTTY
channel. The characters R and Y are "01010" and "10101" in 5-bit ITA2
code, also known as Baudot. Thus they are Boolean
complements of each other.
Switching between the two characters is a stressful test for electromechanical teleprinters.
Repeated over and over, RYRYRYRY... outputs a carrier wave that regularly and rapidly shifts back and forth in frequency.
This signal pattern also provided a test for signal polarity; if polarity was reversed, the test signal would print as "SG".
The corresponding string of complementary characters in 7-bit ASCII
is U*U*U*U*...
Another one is the numeric string "424..." when your FIGS key was jammed.
Teleprinter
A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...
or RTTY
Radioteletype
Radioteletype is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations, later superseded by personal computers running software to emulate teleprinters, connected by radio rather than a wired link.The term radioteletype is used to...
channel. The characters R and Y are "01010" and "10101" in 5-bit ITA2
Baudot code
The Baudot code, invented by Émile Baudot, is a character set predating EBCDIC and ASCII. It was the predecessor to the International Telegraph Alphabet No 2 , the teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of bits, sent over a...
code, also known as Baudot. Thus they are Boolean
Boolean logic
Boolean algebra is a logical calculus of truth values, developed by George Boole in the 1840s. It resembles the algebra of real numbers, but with the numeric operations of multiplication xy, addition x + y, and negation −x replaced by the respective logical operations of...
complements of each other.
Switching between the two characters is a stressful test for electromechanical teleprinters.
Repeated over and over, RYRYRYRY... outputs a carrier wave that regularly and rapidly shifts back and forth in frequency.
This signal pattern also provided a test for signal polarity; if polarity was reversed, the test signal would print as "SG".
The corresponding string of complementary characters in 7-bit ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
is U*U*U*U*...
Another one is the numeric string "424..." when your FIGS key was jammed.