The SmartLIGHT 31 Series (silver) was a nice enough telecater style electric built with and top of the line components. It's real selling point, however, was the FretLight system. Guitars with the FretLight system have LEDs embedded at each fretting position for each string. When connected to the Fretlight PLUS box this allows the fingering for chords, scales to light up on the fingerboard. By connecting to a computer with the SmartPORT 2- PC connection you could also jam along with MIDI tracks and interactive lessons. 

The 31 series guitar has a DIN connector on the side. This functions as a midi input to drive the LED lights - but it can also be used as a MIDI output because the SmartLIGHT 31 series silver was set up ready for RMC MIDI saddles & pickup, but they had to be bought and installed by the user.