Radio Shack TRS-80 Expansion Interface: Operator's Manual Catalog Numbers: 26-1140, 26-1141, 26-1142

This guide walks you through the TRS‑80 Expansion Interface, a versatile add‑on that brings extra memory, storage, and peripheral support to your classic microcomputer. Starting with a clear overview of the case, power supplies, ribbon cable, and cassette connections, it shows how each piece fits together before you even power the system. Detailed illustrations help you install the supplies, route cables, and prepare the unit for future upgrades.

Once assembled, the manual explains the practical benefits: hooking up a screen printer, line printer, or the compact Mini‑Disk system for faster, larger storage, and even a second cassette recorder for smoother data handling. It also covers essential settings, such as switching between Level II commands and overriding Mini‑Disk mode with the BREAK key. Clear cautions and step‑by‑step instructions keep you confident as you expand your TRS‑80’s capabilities.