- A collector discovered an Apollo-era communications test set (Up-Data Link Confidence Test Set) in a warehouse, initially missing its circuit boards but later found in a separate bag.
- The test set was designed by Motorola to verify the Apollo spacecraft's Up-Data Link (UDL) system, which allowed ground stations to send digital commands to the spacecraft.
- Reverse-engineering the device involved analyzing undocumented thumb-sized encapsulated modules using X-ray CT scans and building an automated wiring tracer (Beep-o-matic).
- The test set uses a paper tape reader to load messages, encodes them with sub-bit redundancy and phase-shift keying (PSK), and validates the UDL's responses via panel lights.
- Missing components like the master clock and resonant filters were recreated to restore functionality, enabling the team to generate realistic signals for Apollo communication system reenactments.
- The project highlights the enormous complexity of the Apollo program, where even a specialized test set required extensive effort to understand and operate.