Tcl 10 different chars.

\160\165\164\163 \124\150\145\40\161\165\151\143\153\40\142\162\157\167\156\40\146\157\170\40\152\165\155\160\163\40\157\166\145\162\40\164\150\145\40\154\141\172\171\40\144\157\147 

Characters used: , 0, 1, 2, 3, 4, 5, 6, 7, \

Test program:

set code [read stdin] puts "Characters used: `[join [set ch [lsort -unique [split $code {}]]] {`, `}]` puts "Number of different characters: [llength $ch]"