What is RTTY?

Radio TeleTYpe (RTTY) is a method of sending digital messages between radios using tones. It's a digital mode used in ham radio that can be conversational, similar to technical conversation or rag chewing. 

Here are some things to know about RTTY: 

• RTTY evolved from landline teleprinters in the mid-1800s. The US Navy successfully tested printing telegraphy between an airplane and ground radio station in 1922. 
• RTTY can use several coding methods, such as Baudot, Amtor, and simple ASCII. 
• Modulation: RTTY uses AFSK (audio frequency shift keying) or FSK (frequency shift keying) to transmit tones. 
• Speeds: The most common RTTY speed is RTTY 45 (45.45 baud), but other speeds include 50 baud and 75 baud. 
• The shift is usually 170 Hz, with the upper tone used for idle condition (MARK). 
• Today, RTTY usually involves using a computer and modulation/demodulation software.