ASCII stands for American Standard Code for Information Interchange.
//echo -a $chr(64)
it will display @ and if you type
//echo -a $asc(@)
it will display 64.

based on that statement above i have an idea to convert ascii character to numerics character.
this little snippet allow you to convert a text into numeric characters.

usage: //asc2chr helloworld
output: $+($chr(104),$chr(101),$chr(108),$chr(108),$chr(111),$chr(119),$chr(111),$chr(114),$chr(108),$chr(100))

just simply load this snippet into your mirc`s remote section.

alias asc2chr {
  var %i = 1 
  while (%i <= $len($1-)) {
    var %buff = $instok(%buff,$+($chr(36),$chr(99),$chr(104),$chr(114),$chr(40),$asc($mid($1-,%i,1)),$chr(41)),%i,44)
    inc %i
  }
  echo -a $+($chr(36),$chr(43),$chr(40),%buff,$chr(41))
}