VZ200 Glass RTTY (legacy article)

The VZ200 Glass RTTY Encoder/Decoder was a software project I created in 1984 during the time I was working for Dick Smith Electronics (DSE). It was a plug-in RTTY module to suit the popular VZ200 and VZ300 computers that were available at the time. I wrote the software at home in my spare time. The modem hardware was designed by Rex Callaghan who at the time worked in R&D at DSE and later became technical director. The project was published in Electronics Today International (ETI) in November/December 1984 and was sold throughout Australia and New Zealand by DSE as a kit (Part No. K-6318).

The software was written for the Zilog Z80 microprocessor using Microsoft Assembler on a Dick Smith System 80 computer (a clone of the Tandy TRS-80). The final code was assembled and written to eprom. Sadly I no longer have the original assembler listing but a memory dump of the eprom is provided with the article.

Trivia: If you look on the underside of the PCB you will find the word ‘RANDI’ which is code for Rex AND Ian.

The published ETI articles and the supplied Instruction leaflet are available below.