TPD will be prepared for it consisting of several existing drawings and some notes about which features to synthesize. Machine-readable part marking It is common today for part numbers (as well as serial numbers or other information) to be marked on the part in ways that facilitate machine-readability, such as barcodes or QR codes. Today's advanced state of optical character recognition (OCR) technology also means that machines can often read the human-readable format of Arabic numerals and Latin script. Current revisions of major part marking standards (such as the U.S. military's MIL-STD-130) take pains to codify the most advantageous combinations of machine-readable information (MRI) and human-readable information (HRI). See also Builder's plate Manufacturer model number Global Trade Item Number (GTIN) Pro Electron (European designation and registration system for electronic parts) RETMA tube designation Stock Keeping Unit (SKU) Serial code References Manufacturing Encodings Product classifications Numbers Identifiers