Calculate Check Sum in VB

I need a simple program that will accept a string of hex values transmited from a cash register. The string consists of start code, text data, 2-bytes check sum and end code. This program needs to calculate a check sum and compare it with one received from the register. This is an example: 02 30 2F 32 30 2D 30 30 2F 44 30 2F 45 30 0D . (02 = start code, 30 = block number, 2F -> 2F = data, 45 and 30 = check sum, 0D = end code). The check sum used is: 2 bytes hex number, low-order 8-bit data of the complement of 2 for the sum of text data. So if someone knows what low-order 8-bit... means let me know. I need this in VB6. Can provide more info or more hex dump form the register if needed. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Windows platform (2000,XP) VB6 prefered, but VB.Net 2003 acceptable