I'm writing an Arduino communication library that uses differential Manchester coding (see: http://forum.arduino.cc/index.php?topic=257985.0). I'm wondering how to communicate between two Arduinos that are far enough apart that connecting their power supply grounds is not practical, but without resorting to a wireless system. In that case, a physical communication system that does not need to pass current is needed. I thought of using Toslink fiber optic modules that are typically used for digital audio signals.
The only concern that I have is that the bit rate that my Arduino library (and the Arduino hardware itself) will be able to support is not more than about 20k bps. Digital signals typically carried by Toslink have a bit rate starting at about 1M bps. Since I am not familiar with fiber optic hardware I am concerned that the typical digital audio implementation (e.g. the TX & RX hardware and associated passive components) would not support a relatively glacial data rate of 20k bps.
I could just purchase some Toslink modules and try it out, but I thought that before I buy any parts I would make an attempt to learn about the hardware and ask if there are any inherent pitfalls in sending data at kHz (or slower) rates over Toslink.
So, is this feasible? Are there any obvious problems that will come up?