When using USB reader mode, GP20 supports following file formats:
Document: Adobe PDF 1.0-1.4 (PDF), MS PowerPoint 97-2010 (ppt, pptx), MS Excel 95-2010, Office XP (xls, xlsx), MS Word 95-2010, Office XP (doc, docx)
Photo: JPG (.jpg, .jpeg), BMP (.bmp)
Music: MP3, MP2, MP1, OGG, AAC, WAV
Kindly note document viewing does not guarantee the formatting and looks is the same as what you get in PC due to the document viewer is a simplifed version.