Barcode Check Digit Calculator - Version 1.8 The Barcode Check Digit Calculator & Printing Application supports POSTNET, Code 39, Interleaved 2 of 5, Code 128, EAN, UPC, MSI, Plessy, Code 11, UCC-128, SSCC-18 and SCC-14 barcode specifications. The Visual Basic (VB) 6.0 source code for the application allows developers to print barcodes directly from their applications without the use of DLL or OCX files. VB source code is distributed with the application when installed.