HL7 ACK Codes Explained
Distinguish AA, AE, AR, CA, CE and CR, then trace acknowledgement errors through MSA and ERR.
Read guideHealthcare integration guidance
Technical guides
Practical explanations for common HL7 v2, FHIR, CDA, XML security and certificate problems. Each guide uses synthetic examples and links to a browser-based tool where one is available.
9 practical guidesPrimary sourcesSynthetic examplesFree to read
HL7 v2 and transport
Message structure, acknowledgement behaviour and TCP framing.
MLLP Framing Explained
Inspect VT, FS and CR framing, incomplete payloads, multiple messages and missing acknowledgements.
Read guideHL7 v2 Delimiters and Escape Sequences
Understand MSH-1, MSH-2, non-default separators and escaped data that breaks field parsing.
Read guideHL7 v2 Timestamps Explained
Check DTM precision, UTC offsets, daylight-saving behaviour and double-conversion errors.
Read guideFHIR
Reference resolution, extensions and safe resource processing.
FHIR References Explained
Resolve relative, absolute, contained, logical and urn:uuid references safely in resources and Bundles.
Read guideFHIR Extensions Explained
Process extension URLs, typed value[x] properties and modifierExtension without losing meaning.
Read guideCDA and XML
Namespace-aware processing for CDA and clinical XML.
CDA XML Namespaces Explained
Diagnose XPath queries that return no CDA nodes because the default namespace was not mapped.
Read guidePKI and XML security
Certificate chains, trust boundaries, canonicalisation and digest verification.
PEM and X.509 Certificate Chains
Identify certificate blocks, order chains and separate trust, hostname and private-key checks.
Read guideXML Signature Digest Mismatch
Compare referenced XML, transforms and canonicalised bytes before changing keys or certificates.
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