RYRYRYRY... is a character string that was widely used to test a five-level

teleprinter A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initia ...

RTTY Radioteletype (RTTY) is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link. Radioteletype evolved from earlier landline teleprinter o ...

channel. The characters ''R'' and ''Y'' are "01010" and "10101" in 5-bit

ITA2 The Baudot code is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. ...

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. Test tapes where also made with a repeating RY sequence. This was used by technicians to align the Bias adjustment on equipment such as the 43A1 carrier channel terminal This signal pattern also provided a test for signal polarity; if polarity was reversed, the test signal would print as "SG".Digital Signal Types
/ref> The corresponding string of complementary characters in 7-bit

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...

is ''U*U*U*U*...'' The RYRYRY sequence usage can be seen on the following DDH47 weather station broadcast excerpt: CQ CQ CQ DE DDH47 DDH9 DDH8 FREQUENCIES 147.3 kHz 11039 kHz 14467.3 kHz RYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRY CQ CQ CQ DE DDH47 DDH9 DDH8 FREQUENCIES 147.3 kHz 11039 kHz 14467.3 kHz RYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRY CQ CQ CQ DE DDH47 DDH9 DDH8 FREQUENCIES 147.3 kHz 11039 kHz 14467.3 kHz RYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRY ZCZC 643 WWXX60 EDZW 150900 NAUTISCHE WARNNACHRICHTEN VOM 15.09.2017 UM 09 UTC STRONGWIND GALE STORMWARNINGS FOR GERMAN BIGHT AND BALTIC SEA STARKWIND STURMWARNUNGEN FUER NORD UND OSTSEE NO WARNINGS IN FORCE KEINE WARNUNGEN IN KRAFT

References

{{reflist History of telecommunications Test items