Function NumToChar(MyRange As Range)
Dim i As Long, Iter As Long
Dim ya As Variant
Dim NewNum As String

Const MyDict As String = "ABCDEFG" 'Справочник символов

If MyRange.Count > 1 Then NumToChar = CVErr(xlErrRef): Exit Function
If Len(MyRange) = 0 Or Len(MyRange) > Len(MyDict) Or Not IsNumeric(MyRange) Then NumToChar = CVErr(xlErrValue): Exit Function

ReDim MyArray(1 To Len(MyRange))
Iter = 1
For i = 1 To Len(MyRange)
    ya = Application.Match(CInt(Mid(MyRange, i, 1)), MyArray, 0)
    If Not IsError(ya) Then
            NewNum = NewNum & Mid(MyDict, ya, 1)
        Else
            MyArray(Iter) = CInt(Mid(MyRange, i, 1))
            NewNum = NewNum & Mid(MyDict, Iter, 1)
            Iter = Iter + 1
    End If
Next

NumToChar = NewNum

End Function

Function DigitsToChars(ByVal s As String)
  Dim n As Long, a As Integer
  a = Asc("A")-1
  s = Replace(s, Mid(s, 1, 1), Chr(a))
  For n = 2 To Len(s)
    If Mid(s, n, 1) Like "#" Then
        a = a + 1
        s = Replace(s, Mid(s, n, 1), Chr(a))
    End If
 Next
  DigitsToChars = s
End Function

Function DigitsToChars(ByVal s As String)
  Dim n As Long, a As Integer
  a = Asc("A")
  For n = 1 To Len(s)
    If Mid(s, n, 1) Like "#" Then
        a = a + 1
        s = Replace(s, Mid(s, n, 1), Chr(a))
    End If
 Next
 DigitsToChars = s
End Function