the US Coast Guard nearly continuously RTTY systems are also fielded by amateur radio operators, and are popular for long-distance contacts One regular service transmitting RTTY meteorological information is the German Meteorological Service (Deutscher Wetterdienst or DWD). The DWD regularly transmit two programs on various frequencies on LF and HF in standard RTTY (ITA-2 alphabet). The list of callsigns, frequencies, baud rates and shifts are as follows: The DWD signals can be easily received in Europe, North Africa and parts of North America. Pronunciation RTTY (in English) may be spoken as "radioteletype", by its letters: R-T-T-Y, or simply as /ˈɹɪti/ or /ˈɹəti/ Media See also Related technical references Asynchronous serial communication Modem Teleprinter Telex Types of radio emissions UART Digital HF radio communications systems ACARS, used by commercial aviation – packet based CLOVER2000 developed by HAL company, USA, for Radio Amateur application Hellschreiber, a FAX-RTTY hybrid, very old system from the 1930s MFSK including COQUELET, PICCOLO and Olivia MFSK, also referred to generically as Polytone MT63, developed and used by Radio Amateurs and some government agencies Navtex, used for maritime weather reports, with FEC error control code using the SITOR-B system PSK31 and PSK63 developed and used by Radio Amateurs PACTOR, a packet SITOR variant, developed by Radio Amateurs in Germany AX.25, the original digital PacketRadio standard developed by Amateurs Automatic Packet Reporting System, built on top of AX.25, used by Amateurs and Emergency services and which includes GPS Positioning Q15X25, a Radio Amateur created packet format (AX25), similar to the commercial X25 standard Fast Simple QSO or FSQ, an HF mode developed by Radio Amateurs for us in NVIS and sunrise/sunset conditions. SITOR, (SImplex Teleprinting Over Radio) a commercial RTTY variant with error control (the Radio Amateur version is called AMTOR) Sailmail, a commercial HF mail system WSJT, a computer program used for weak-signal radio communication between amateur radio operators References Further reading Getting Started on RTTY, Getting started on RTTY using MMTTY RTTY.COM, a repository of Amateur RTTY information British Amateur Radio Teledata Group (BARTG) RTTY Demodulator Development by Kok Chen, W7AY. A technology review for the early period until ca 1965. Quantized radio modulation modes Military radio systems Amateur radio Wireless communication systems