9F39

Point-of-Service Entry Mode is a single ISO 8583 code stating exactly how the PAN and PIN were captured for this transaction - chip, contactless, manually keyed, magnetic stripe, and several other methods - information the acquirer and issuer host both consume heavily for risk scoring, since the capture method itself is one of the strongest signals available for how much to trust a given transaction's data. It's related to Transaction Type (9C, covered earlier) and Track 2 Equivalent Data (57) as part of the same terminal-supplied transaction-context bundle, and because entry mode drives risk scoring so directly, it's also a field fraud actors specifically try to manipulate: a terminal falsely reporting a chip-read transaction as manually keyed, or vice versa, is misrepresenting exactly the signal a host's risk model relies on most, which is why entry-mode integrity checks, comparing the reported code against what the transaction's own data actually supports, like the presence of a genuine cryptogram, are a standard part of host-side fraud detection. See EMV 4.4 Book 3.