Transferring Microsoft Excel files to a TI-89 calculator, particularly the non-titanium model, is not straightforward. The calculator does not support the standard .xls format. Instead, users are advised to convert Excel files to .csv or .txt formats, as these are ASCII files with standard delimiters that many systems can interpret. While there is limited information available specifically for the non-titanium TI-89, searching for "Excel Ti-89" may yield more relevant results, although much of the available content focuses on the TI-89 titanium model.