The dulcimer is a mediaeval stringed instrument, with ten or more strings stretched over a flat shallow sound box. Small hammers are used to strike the strings. It came from Asia to Europe in the 12th century. Various similar instruments, with names like cimbalon, santouri and hackbrett  and the zither, are still in use today for folk music in Eastern Europe.

The Zither is a modern European descendent of the dulcimer, found in Switzerland, Austria and Southern Germany.  It has a set of accompaniment strings, strummed with the 4 fingers of the right hand. and a few melody strings, which are plucked with a plectrum held in the thumb of the right hand. The left hand is used to stop the melody strings against the frets, just like on a guitar.  A MIDI sound for the zither can be obtained under MIDI mode GS using Instrument 15 (dulcimer/santur) with bank select MSB of 16,  LSB = 0.

The range and tuning of dulcimers and zithers vary enormously, there seems to be no fixed standard. The typical pitch range of a simple zither with only 15 strings, giving two octaves, is illustrated above. This is a diatonic scale , there are no flats or sharps, so the instrument can only play in a single key unless it is re-tuned. But there are many other bigger and complex zithers which have a large pitch range and chromatic capabilities.