Radioteletype
From Free net encyclopedia
(Redirected from RTTY)
Radioteletype (RTTY) is a telecommunications system consisting of two teleprinters linked by a radio link.
Contents |
[edit]
How it works
RTTY uses a variety of different modulation methods, of which frequency shift keying are the most common.
- Coding used is typically 5-bit ITA2 code (also known as the Baudot code), which is used asynchronously with start and stop bits.
- At least one common RTTY system uses 6-bit ITA2 character codes.
- More modern systems use 7-bit or 8-bit bytes.
[edit]
Slow by modern standards
RTTY is extremely slow by modern standards; a typical baud rate for RTTY operation was 45 baud (approximately 60 words per minute).
- The combination of low baud rate with robust FSK modulation makes RTTY highly resistant to most forms of radio interference, second only to Morse code.
[edit]
Spectrum efficiency
Image:HF RTTY-mode-comparason.png
[edit]
Primary users
Principally users that need robust shortwave communications
- Various navies of the world
- Various armies of the world
- Diplomats, especially in Africa and parts of Asia
- RTTY systems are also fielded by radio amateurs.
[edit]
Pronunciation
The pronunciation of RTTY is disputed
- In very few applications, notably the U.S. military, radio teletype is known by the acronym RATT rather than RTTY.
- Those who are actively engaged in amateur RTTY communications pronounce RTTY not by its initials but as "ritty".
[edit]
Spectrum usage
Image:MT63 Packet RTTY-comparason.png
[edit]
See also
- Sailmail, a commercial HF mail system
- SITOR, an RTTY variant with error control.
- PACTOR, a packet SITOR variant
- Hellschriber, a FAX-RTTY hybrid
- ACARS, used by commercial aviation -- packet based
- Navtex, used by maritime navigation
- MT63, used by Hams and some government agencies
- PSK31 & PSK63
- MFSK
- COQUELET, also referred to generically as Polytone
- PICCOLO, also referred to generically as Polytone
- CLOVER2000
- Q15X25, a HAM created packet formatde:Radio Tele Type