extern char *tx_num_to_cabbr(int num) ;
extern char *tx_num_to_cname(int num) ;
extern int tx_cname_to_num(char *name) ;
extern int tx_cabbr_to_num(char *abbr) ;
extern char *tx_cabbr_to_cname(char *abbr) ;
extern char *tx_cname_to_cabbr(char *name) ;