MRRC Modern / `mrrc_modern` SDD — Software Design Description

Web Remote Control for supported radios (Yaesu FT-710, Icom IC-7300 / IC-7300MK2)
IBM Team Solution Design (TeamSD) v2.3.2 aligned documentation set

Purpose

This SDD is the canonical design record for the mrrc_modern codebase — a Python FastAPI server that bridges a browser to one or more supported HF/50MHz transceivers via pluggable radio backends. It captures requirements, architecture, design decisions, component boundaries, operational model, capability inventory, known gaps, and evolution history.

Runtime facts are derived from server.py, backends/*, audio_handler.py, radio_state.py, poll_scheduler.py, scope_handler.py, config.py, opus_rx.py, static/index.html, static/ft710_main.js, static/ft710_ui.js, and static/modules/*.

Document Index

#	Chapter	ART Code	File
1	Executive Summary	-	01-executive-summary.md
2	Business Direction	BUS 411	02-business-direction.md
3	Project Definition	ENG 343	03-project-definition.md
4	System Context	APP 011	04-system-context.md
5	Non-Functional Requirements	ART 0507	05-non-functional-requirements.md
6	Use Case Model	ART 0508	06-use-case-model.md
7	Subject Area Model	APP 408	07-subject-area-model.md
8	Architecture Decisions	ART 0513	08-architecture-decisions.md
9	Architecture Overview	ART 0512	09-architecture-overview.md
10	Service Model	ART 0582	10-service-model.md
11	Component Model	ART 0515	11-component-model.md
12	Operational Model	ART 0522	12-operational-model.md
13	Feasibility Assessment	ART 0530	13-feasibility-assessment.md
14	Version History	-	14-version-history.md
15	PTT Safety Architecture	ART 0535	15-ptt-safety-architecture.md

Quick Facts

Attribute	Value
Document ID	SDD-MRRC-MODERN-2026-001
SDD Version	V2.30
Baseline Date	2026-08-29
Status	v1.12.1 Windows Stable published from a verified 633-test build; ox-alpha hardening line merged after publication (ships with the next release); IC-7300/MK2 physical hardware acceptance pending; FT710Android device acceptance pending; I8/I10/I12 resolved, I9/I11 partially resolved (remaining: forced first-login change; iOS watchdog/scenePhase); open issues tracked in §13.4
Project	MRRC Modern / `mrrc_modern`
Primary Radios	Yaesu FT-710; Icom IC-7300 / IC-7300MK2 (selectable via backend)
Backend Selection	`MRRC_RADIO_MODEL=ft710\\|ic7300\\|ic7300mk2` (default `ft710`)
Runtime	Python 3.12+, FastAPI, Uvicorn, NumPy, PyAudio
Frontend	HTML5, CSS3, vanilla JavaScript, Web Audio API
Transport	HTTP/WS for browser; Serial CAT (Yaesu) or USB CI-V (Icom) for radio; FT4222 SPI for FT-710 scope; CI-V 0x27 spectrum for IC-7300
Default Entry	`http://localhost:8888`

System at a Glance

Browser (iPhone / Desktop / Tablet)
  | HTTP + WebSocket: /WSradio /WSaudioRX /WSaudioTX /WSspectrum (+optional /WSatr1000)
  v
FastAPI/Uvicorn MRRC Server (server.py)
  | Pluggable backend selected by MRRC_RADIO_MODEL
  |   ft710: Serial CAT (USB Enhanced COM Port, 38400 baud) → Yaesu FT-710
  |          FT4222 SPI (scope_pipe subprocess) → real spectrum data
  |   ic7300/ic7300mk2: USB CI-V serial (115200 8N1, addr 0x94/0xB6) → Icom IC-7300/MK2
  |                     CI-V 0x27 spectrum on the same port (display+data enabled; 44-segment newest-data queue)
  | PyAudio (USB Audio device) → RX/TX audio capture/playback
  | Opus codec (libopus) → compressed audio transport
  v
Yaesu FT-710 or Icom IC-7300 / IC-7300MK2 Radio

Capability Summary