Western keyboard...

We have enunciated again and again that we need many, many microtones to produce Indian music. Still, in this chapter, we are going to use a conventional, Western keyboard to learn about Indian music. It is almost like the Indian music is an analog entity and we are trying to quantize or digitize it into twelve keys, knowing fully well that we will have something akin to truncation (approximation) errors.
But before we begin, let us define one more term - the 'note'. The 'note' is just a primitive element of a musical phrase. An analogy will be the concept of a 'syllable' in a spoken word or a letter in a written word.
For example, in the nursery rhyme 'Baa baa black sheep' there are four 'notes', namely 'baa', 'baa', 'black' and 'sheep'. By a curious coincidence, this line also has four syllables - and we have managed to make a 'note' for each syllable. The concept of a note is so simple that even if you know nothing about music, you may be able to tell how many notes there are in a (simple) melodic pattern.
On the other hand, consider 'Roop tera mastana, pyaar meraa...' When spoken, the word 'roop' has only one syllable. However, when sung, it is distorted to sound like 'roo - pu' and uses TWO 'notes'. Similarly, when the singer goes 'pyaar meraaaa', he glides the end of the word 'meraaaa' into several 'notes'. The term 'note' and 'tone' are different and make sure you understand it. The word 'tone' is essentially a frequency, whereas the 'note' is the smallest part of a melody and could last one 'tone' plus possible microtones. The Indian word for 'note' is 'Swaram' or 'sur'. Now we are ready to get more technical and tinker with any commercially available keyboard to learn about Indian classical music. A diagram showing a typical keyboard octave is given in Table II, except that now we have labeled the keys with Indian names. Onceagain, eight out of the twelve keys have unique labels, whereas four of the remaining keys - keys 3, 4, 10 and 11 - have ambiguous (two possible) names. Unlike the Western notation, the keys with ambiguous labels are both black and white (two of each).
In the Indian system, we do not use alphabets to label keys. Instead, we use short, meaningless (please don't beat me to death on this - I know there are etymological reasons for choosing these set of syllables) syllables which go - Sa ri ga ma pa dha ni. These seven syllables are actually mnemonics to represent the 'notes' or 'Swarams' in Indian music. They are referred to as the 'Saptha Swarams' or 'Seven Swarams'. So, confusing as it may sound, in Indian music, we use the 'notes' to represent the 'tones'. Upon looking at Table II some more, we see that some THREE keys can be designated as 'ri', (even though they are designated as ri 1, ri 2 etc, they are all 'called' ri) three keys as 'ga', two as 'ma', three as 'dha' and three as 'ni'. However, there is no ambiguity when we want to press the keys corresponding to 'Sa' or 'Pa' - they are unique.
This notation (and this set of seven 'notes') is also called the 'Solfege notation' (in the West). Remember, even in the West, there is a solfege notation which goes do, re, me, soh etc. Basically, the solfege notation is a 'singable' set of syllables which helps us describe a musical melody. It will sound quite ridiculous to sing out words like 'C, C sharp, E flat' - instead of 'do fa la' when we hit the keyboard keys.