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Architecture Models

Reference diagrams for the Dex Health platform — system context, tele-consult sequencing, and the compliance data flow.

System Context
Client surfaces, gateway, service plane, data plane, and the split-out media plane
BLE devices Linktop · Valdus Super Admin portal Clinical portal Patient companion API Gateway EU data residency Identity & MFA Telemetry Ingest Scheduling & Consult Billing / GeSY Notifications EU PostgreSQL Nicosia (primary) Object store (reports) Append-only Audit Log Media plane Token Service AV SFU real-time media DTLS-SRTP media

All application traffic enters through the API gateway; PHI never leaves the EU boundary. Real-time audio/video takes a separate media plane — clients fetch short-lived credentials from the token service and connect to the SFU directly over encrypted media links.

Audio/Video Consult Sequence
From appointment creation to billed minutes — settings-driven, consent-gated
Patient app Scheduling module Token service AV SFU Clinical portal 1 · appointment created (mode: video|audio · join window · reminders — from appointment settings) 2 · reminders — 24h email · 1h SMS 3 · patient joins within window → token request 4 · tokens issued to both parties 5 · media session — video or audio-only · fallback video→audio 6 · optional consent-gated recording 7 · session log + duration → billing minutes (CPT 99457)

The appointment settings module owns modality, join window, reminders, and recording consent — the call layer only honours them.

Compliance & Data Flow
Consent gate, EU-resident processing, the human-supervised AI loop, and DSR handling
EU data residency Data subject (patient) Consent gate GDPR Art. 6/9 Processing telemetry · chat · billing outputs Clinician care decisions AI inference EU AI Act high-risk output labelled Human review (clinician) action no autonomous clinical action DSR queue requests intake Erasure / Export Art. 17 · Art. 20 audit writes Append-only Audit Log

Nothing reaches processing without passing the consent gate; nothing reaches a patient from AI without a clinician in the loop. Consent decisions, processing events, AI inferences, and DSR outcomes all land on the same append-only audit log — the single evidence trail for supervisory review.

Related documents
Written references that accompany these models