Test Binary File

I've got an error with the way I'm using readBin on a binary file of unknown internal structure.  I know the structure consists of rows and columns, but I'm not sure how many of each.  

So, does anyone know of a valid test set of binary data that I could reference while trying to figure out the technique of using readBin? 

It would be really helpful to try out readBin on a readily available and understood binary file instead of starting with one of dubious internal structure.  

Thank you again for your help and feedback.