Tamiz in ancient time was divided into prose(iyal), music (isai), drama (n^Atakam). But today very less people even among Tamiz speaking know about the Tamiz isai. Tamiz music has a lot of similarities with carnatic music. There are people who argue that carnatic music came from Tamiz music. The reference to Tamiz music is there in ancient Tamiz literature like SilappadhikAram.

The following list gives the equivalent in Carnatic music

Tamiz music    Carnatic music

paN            rAgam

padham         swaram

thALam         thALam

ArOhaNam               ArOchai

avarOhaNam             amarOchai

padham Ezu  - saptha swaram - 

        kural          shadjam 

        thuththam      R^ishabham 

        kaikkiLai              panychamam 

        uzai           madhyamam 

        iLi            panychamam 

        viLari         dhaivatham 

        thAram         nishadham 

In thEvAram the following paNs are used. The entire thEvAram is arranged in sequence with respect to the paNs. (The list below is not in the same sequence as that is followed in thirumuRais). In the 9 th thirumuRai a paN which is not used in other thirumauRai called sALarApANi is used.

        paN                    rAga

1. n^attapAdai                 n^Attai

2. kolli                       n^avarOs

3. in^dhaLam                   n^Adhan^AmakriyA

4. kurinychi                   arikAmbhOdhi

5. chen^thuruththi             madhyamAvadhi

6. yAzmUri                     atAnA

7. chIkAmaram                  n^Adhan^Amak kriyA

8. n^atta rAkam        pan^dhuvarALi

9. thakkarAkam                 kAmbOdhi

10. pazan^thakkarAkam          sudhdha sAvEri

11. pazam panychuram           shaN^karAparaNam

12. thakkEsi                   kAmbhOdhi

13. chevvazi                   yadhukula kAmbhOdhi

14. piyan^dhaik kAn^dhAram     n^avarOs

15. kAn^dhAram                 n^avarOs

16. kAn^dhAra panychamam       kEdhAra gauLai

17. kollik kauvAnam            n^avarOs

18. kausikam                   bhairavi

19. panychamam                 Akiri

20. sAdhAri                    pan^dhuvarALi

21. puRan^Irmai                bhUpALam

22. an^dhALik kuRinychi               sAmA

23. mEkarAkak kuRinychi               n^IlAmpari

24. viyAzak kuRinychi          saurAshtram

25. sALarApANi

The following are structures and so no specific rAga assigned.

1. thiruk kuRun^thokai         

2. thirun^Erichai              

3. thiruviruththam             

4. thiruth thANdakam           

In the above table some of the paNs have same carnatic rAgA equivalent. (like kolli, kolli kauvANam have equivalent as navarOs). There should be some differences. People who have good knowledge on both music systems will be able to explain.

In the first seven thirumuRais (thEvAram as they are collectively called), nineth thirumuRai and some portions of eleventh thirumuRai (kAraikkAl ammaiyAr) the paN for every padhikam is specified and it is supposed to be sung in only that specified paN. There is a paN thiruththANdakam which is found in many of by thirun^Avukkarasar 's thEvArams and they are the oldest usage of that particular paN. So thirun^Avukkarasar is also called thANdaka vEn^dhar.
As vINA is the major music instrument in carnatic music, yAz was the most famous music instrument that gets mentioned in many of the ancient Tamiz literature. It is also a string instrument like vINA. There were a lot of musicians called pANar used to play the songs in the instrument yAz. A lot of saN^gam literature were written with the pANar as main characters.(perumpANARRuppdai, chiRupANARRuppadai etc.). Thiru n^IlakaNta yAzppANar of thiru erukkaththam puliyuur used to play the padhikams of thiru nyAna samban^dhar in yAz. More information on this instrument yAz can be found in "yAzn^Ul" written by swami vibulAnan^dha. Some of the other music instruments that are referred in thirumuRai are vINA (string instrument), kokkarai, kudamuzA (thALa instruments). Some hymns in "kallAdam" describe about these instruments.
All the thEvArams were locked up in a room in the chithambaram temple for some centuries. When the "Shiva pAdha sEkara" "thirumuRai kaNda chOza" emperor rAjarAjan took them out, the paN for many of the padhikams were not known. He asked madhaN^ka chULA maNiyAr, a woman successor came in the yAzpANar family specified the paN for all the padhikams and the padhikams are sung only in that specified paN.
The twelfth thirumuRai periya purANam tells about the making of flute and playing on the flute in AnAya n^AyanAr purANam songs 13, 24-28. kallAdam has reference to lot of music instruments.

Note:
Some of the information here are incomplete (like rAgA equivalents). Sending more information will be appreciated.