tax type and tax rate

Hello Gurus,

In OBCD transaction we are maintaining partner type , partner number , external tax type , tax rate , country, tax code. for example in one entry tax type is C3 , tax code is TS and country IT , Partner type LS and partner number 1150. its fine . Here my doubt is what is the realation between tax type C3 and tax code TS. ??? where was the link between these two.

Suppose to maintain new entry in OBCD if i know tax code and i dont know tax type . then how can i find tax type for a tax code which i have to use?