There are seven basic thalas :

1. Dhruva talam

2. Matya Talam

3. Rupaka Talam

4. Jampa Talam

5. Triputa Talam

6. Ata Talam

7. Eka Talam

In a tala, the drtham has two units
and anudrtham (if it is part of a talam) has 1 unit and this is a constant.
But the units of the laghu vary according to the jaathi.

Jaathi
1. Thisra Jaathi
2. Chatusra Jaathi
3. Kanta Jaathi
4. Misra Jaathi
5. Sankeerna Jaathi |
Aksharams
3
4
5
7
9 |

So, depending upon the jaathi, the units
of the laghu varies. And the jaathi of the talam is determined by the jaathi
of the laghu. Also, depending upon the jaathi of the laghu, the aksharams
of the tala vary. For instance, the Triputa talam has the following angams
- one laghu and two drthams and symbolically 1 0 0. Now, if the Triputa
is Thisra Triputa, the laghu will have three aksharams

and the thala will have three aksharams.
If the talam is Kanda Triputa, the laghu will have 5 aksharams and the
tala will have 9 aksharams

Thus the 7 talams in combination
with the 5 jaathis gives 35 talas in Carnatic music. Among these, the Chatusra
Jaathi Triputa (Adi), Rupakam, Kanda Chapu, Misra Chapu are the most widely
used talam. All the 7 talas in one of the jaathi is taught in the preliminary
exercise of "Alankaram". These talas are called desi talas.