CareTV Fax + SMS Architecture - 2026-08-20 v004

Browser/UI:
- No modem control.
- No carrier credentials.
- Calls localhost API only.

Windows agent:
- Owns queues, logs, hardware adapters, retries, and delivery status.
- /api/sms queues an SMS job.
- /api/fax queues a fax job.
- Current v004 implementation is a safe local spool/queue layer.
- Hardware transmission adapters are intentionally separate.

Recommended open adapters:
SMS:
- standards-based USB/LTE modem exposing a serial AT-command interface
- later: SIP/SMS or carrier adapter behind the same API contract

Fax:
- analog fax modem + real analog line, OR
- SIP/T.38-capable gateway/provider where interoperability is acceptable
- incoming fax lands in D:\_CareTV-Communications\fax\inbox

Important:
- v004 queues jobs but does not claim to transmit them until a real modem/telecom adapter is installed and configured.
- Long-lived carrier/AWS credentials never belong in HTML or JavaScript.
- The front-end API remains stable when Windows is replaced by a future CareTV server OS.