I have a range of cells that use the Time Quick Entry method from Chip
Pearson's website. I want to allow specific text entries ("DQ" or "DNS") but
I don't want to allow any other text entries. I added the following code to
allow the text, and convert it to all caps, but I'm not sure how to prevent
other text entries?

If Application.WorksheetFunction.IsText(Target.Value) = True Then
Application.EnableEvents = False
Target.Value = StrConv(Target.Value, vbUpperCase)
Application.EnableEvents = True
Exit Sub
End If

Thanks,
~ Horatio