I need someone to help me find how the CRC is calculated in a data. Please see the attached Excell file. I have listed data from 17 different sets of data. They are all from the same type of device. On the top row of the Excell file, I have listed the serial number and expiration date of the device. Rows 2-129 list the data for each device under the corresponding column. I have figured out that the serial number of the device is in the data rows 5-11.
If I change any of the data, the machine rejects the code. It seems that there is some kind of a CRC being calculated by the device from all the data.
I need your help in figuring out how this device is calculating the CRC, so that I can change part of the data without having the device reject the data.
Specifically, I need to be able to change the serial number in the data and know how to generate the new CRC so that the device will not reject the revised data.
I have also provided the expiration date that is written on each device (top row, next to serial number). I am not sure if the expiration date is coded in the data. I could not find any matching data that would match the serial numbers. If you find it, please let me know where in the data is the expiration date.
Thank you for your help.