It has been a long time since I last wrote software for the RTTY mode. The newly released version 3.10 adds RTTY to CommCat using the MMTTY engine. My first RTTY program, RTTY89, was released in 1979. Much has changed since then.

RTTY stands for "Radio TeleType". Most RTTY operation in 1979 used a mechanical teleprinter for printing and Terminal Unit (TU) for demodulating the two-tone audio signals fed from the receiver. The most desired teleprinter of the day was the Model 28, made by the TeleType Corporation. It was a mechanical wonder. Here is a [URL=""]link[/URL] to a YouTube video showing the Model 28 in action.

The first program I wrote for the Heathkit H8 was a driver that enabled the use of a teleprinter as a system printer. No matter that the Model 28 and its predecessors were upper case only...for a computer that used a cassette recorder to load programs, any printer at all was amazing. The video monitor kit sold by Heathkit was also upper case only, so nothing was lost.

The next programming challenge after the driver was a send/receive RTTY program. Version 1 was provided on cassette tape. After Heath released the floppy disk drive and a disk operating system for the H8, I added more features to the program and released it on disk. This program was sold through the Heathkit catalog as RTTY89, with sales in the hundreds.

RTTY89 was the last ham program I wrote until I started CommCat in 1999. For a number of years, digital mode programs have used the computer's sound card in place of a TU. RTTY has been joined by scores of new digital mode programs as the FCC has relaxed rules.

Through the generosity of Makoto Mori, JE3HHT, the hard work creating sound card software has been made easy by the freeware MMTTY engine. Even so, there were a number of speed bumps along the way. This has been a learning experience for me! It is nice to offer a new RTTY program, 30 years later.