Finished my board today and have just completed fine tuning the voltage comparator to make sure the RS232 signals are being sent and received correctly.
I've got the IR emitter and IR phototransistor facing eachother on the board for testing but now that I've confirmed it's working I'll take them off and put them in some kind of enclosure which will attach via a magnet on a meter port.
Still looking for that MeterMate program though so won't be able to test until I can get a copy.
Nice job. I remember many years ago making opto leads for the Calmu metering in the early 1990's. The leds were attached in a plastic housing which slided into a slot on the Calmu meter to make the comms connection.
Many of my meters are turning around on the web.
Have a look on YouTube