Posts tagged with “Radio Shack”

The Model III to 4 Upgrade Kit

The TRS‑80 Model 4, introduced in 1983, was 100% software compatible with its predecessor, the TRS‑80 Model III. A cassette-based Model 4 behaved identically to a cassette-based Model III and could run all Model III software. But a disk-based Model 4 could also run new Model 4 software that exposed features unique to the Model 4, such as extra memory and a larger text resolution.