That IS good info (thank you), but I was already aware of it's information. It does not, unfortunatly, cover what I was trying to do. The origianl goal was to create an input mask or data validation rule that allows alphas & numerics but not symbolics or spaces while still retaining a variable length structure. I actually found a decent workaround I think with using an input mask of "aaaaaaaaa" then using the validation rule of Instr([MyField]," ") = 0. This combination seems to have accomplished the goal mostly.