This was originally just a small circuit board made for a specific test and then put aside. It had one external voltage input, switched betwen 12V and 24V ranges, and a thermister and a photocell were soldered onto the board. It required a power supply regulated to 5.12V. Later, when re-programming the Logging Terminal it was dolled up in a small box with these changes to test it: 1. A second input was added at 5V fullscale, and both inputs are now connected via binding post terminals. 2. A 78L05 regulator was added, boosted to 5.12V, with a 5.5x2.1 mm jack to connect the power supply. 3. A switch and board is mounted on the top cover to provide a range of serial output options.

These are the circuit diagrams
This is the processor program