Hi,

If A UDF is not allowed then the following seems to work…

F8 on Sheet1 needing validation. On a spare sheet (I used Sheet3) in
A1 enter a string consisting of all the allowable characters. In this
case…

", -1234567890"

in A2 on the spare sheet enter the following formula...

=IF(MID(Sheet1!$F$8,ROWS($A$2:$A2),1)="","BLANK",M ID(Sheet1!$F
$8,ROWS($A$2:$A2),1))

In B2 on the spare sheet enter this formula...

=IF(A2="BLANK",0,IF(ISERROR(FIND(A2,$A$1)),0,--(FIND(A2,$A$1)0)))

Fill the formulas in A2 and B2 down so that the number of rows with
the formulas is not less than the number of characters in the longest
possible string to be entered into F8. (I filled down to row 31).

In B1 on the spare sheet enter the following formula...

=IF(SUM(B2:B31)=LEN(Sheet1!F8),TRUE,FALSE)

With B1 selected go Insert|Name|Define... then type
"IsF8Valid" (without the speech marks) into the Name box. Click Add
then OK.

Select F8 then apply the data validation using "=IsF8Valid" (without
the speech marks) as the Custom Formula.

Ken Johnson