A Hewlett Packard Infrared Signal Decoder
Martin Hepperle
June 2015
Several Hewlett Packard pocket calculators are able to send printer output via Infra-Red (IR) signals to a small portable printer. They use an HP-specific transmission protocol which is also called “Red Eye”. This protocol is different from the better known IrDA protocol. This document gives a brief overview of the format and describes hard- and software to build a decoder system for this protocol.
This system allows receiving the “Red Eye” signals with a computer via a serial or an USB interface.