Hello Derekskchan, get the example at: http://www.ustr.net/files/download.shtml go to the bottom of the page, and look for CRC16.BAS, there is also a CRC16.EXE that was done in assembler in 1987, you can use it tor check your program. Wagner. PS: This post should be flagged [OT] since it is not related to PIC, ok? derekskchan wrote: > > Does anybody has the CRC16 routine written in Visual Basic ? > > Any help appreciated > > Thanks