You need a high-quality USB-to-ALDL (12-pin) adapter or an OBD1.5 (16-pin) adapter , depending on your vehicle's year. Companies like Moates (historically) and Redat/Redal or various specialized eBay/Amazon boutique builders supply these FTDI-chipset-based cables.
Setting up a GM Tech 1 emulator requires a precise combination of hardware components to bridge the gap between a modern PC and vintage automotive networks. The Software Layer gm tech 1 emulator
For those who don't want to hunt down 30-year-old hardware, a laptop-based setup is the closest alternative. You need a high-quality USB-to-ALDL (12-pin) adapter or