Function modules

Hi ,

Could any one telme what the below fms do with an example :

CONVERSION_EXIT_ALPHA_INPUT

CONVERT_DATE_TO_EXTERNAL

CONVERT_DATE_TO_INTERNAL

CONVERSION_EXIT_MATN1_INPUT

CONVERSION_EXIT_AENNR_INPUT

Your answers would be rewarded with points if helpful..

Thanks in advance,

Vishwanath.