OpenWebNet Protocol & WHO Specifications Archive¶
Welcome to the OpenWebNet Protocol & WHO Specifications Archive. This document serves as the official open-access registry of technical manuals, frame syntax, dimension definitions, and specifications published by BTicino / Legrand for the OpenWebNet protocol across MyHOME systems.
Historically, these technical specifications were distributed through the MyOpen Community portal (myopen-legrandgroup.com / myopen-bticino.it), which is no longer active. To ensure permanent access to accurate protocol documentation, this centralized registry preserves the complete protocol reference.
📚 Master WHO Family Inventory¶
The table below catalogs every known OpenWebNet function family (WHO), its official Legrand document title, current known version, archive status, and Home Assistant platform mapping:
| WHO | Subsystem / Function | Official Document Title | Known Version & Date | Status | Home Assistant Entity | Notes & Supported Hardware |
|---|---|---|---|---|---|---|
| 0 | Scenarios (Basic) | Open Web Net Language (Scenarios) |
v2.0.0 (2010-10-01) | Verified | event, automations |
32 standard scenarios (03551, 88301, F420, IR 3456). |
| 1 | Lighting | Who = 1 LIGHTING |
v1.1.0 (2014-11-17) | Verified | light |
ON, OFF, Dimming (1-100%, 10 levels, steps), Blink, Timer, Speed of transition. DALI tunable white / RGBW via F429/F429G. |
| 2 | Automation | Messages - Automation |
v1.0.0 (2015-11-12) | Verified | cover |
Roller shutters, venetian blinds, motorized curtains, gates. Standard UP/DOWN/STOP and absolute positioning percentage (Legrand 67557). |
| 3 | Load Control (Legacy) | OpenWebNet_Community_3_LoadControl |
v1.0.0 (2006) | Verified | switch, sensor |
Priority-based load disconnection central unit (F421). Inhibit/force actuators. |
| 4 | Thermoregulation | Open Web Net Language - Heating adjustment |
v2.0.0 (2013-11-27) | Verified | climate, sensor |
4-zone / 99-zone central units (3550), standalone thermostats (L/N/NT4691), external probes (3475). |
| 5 | Burglar Alarm | MyHome Burglar Alarm |
(2008-02-13) | Verified | alarm_control_panel |
Central units (3485, 3486), partition arming/disarming, panic alarms, gas/water technical alarms. |
| 6 | Door Entry Call & Lock | OpenWebNet_Community_DoorEntry |
v1.0.0 (2006) | Verified | lock, switch |
Audio door entry calls, door lock release (*6*10*<WHERE>##), staircase light, camera switching. |
| 7 | Video Door Entry / Multimedia | Open Web Net WHO=7 |
v1.0.1 (2011-12-01) | Verified | camera |
Video session establishment, camera selection, video stream routing over IP for Video Server F453AV. |
| 9 | Auxiliary Channels | OpenWebNet_Community_Auxiliary |
v1.0.0 (2006) | Verified | switch |
Auxiliary channels (AUX 1 to AUX 9) for triggering remote relays or annunciators without occupying lighting addresses. |
| 13 | Gateway Management | OpenWebNet_Community_2_device |
v1.0.0 (2006-06-13) | Verified | Diagnostics | Date/time synchronization (*#13**0*...), firmware version query, IP configuration, MAC address, uptime, reboot. |
| 14 | Actuator Safety Lock | Light & Shutter Actuators Lock |
v1.0.0 (2008) | Verified | Diagnostics, button, lock |
Physical endpoint lock/unlock. Lock (*14*0*<WHERE>##), Unlock (*14*1*<WHERE>##). Inverts/locks physical wall buttons. |
| 15 | CEN Scenario Control | CEN Frames for Scenario Scheduler |
v1.0.0 (2010-10-01) | Verified | event, device triggers |
Pushbutton scenario events for Scenario Scheduler (MH200, MH200N, Legrand 03565): Short press, extended pressure, release. |
| 16 | Sound Distribution | OpenWebNet_Community_4_soundsystem |
v1.0.1 (2011-11-24) | Verified | media_player |
Multi-room audio matrix & zone control: Amplifier ON/OFF, volume control, audio source routing, tone equalizers (F441, F450, 3487). |
| 17 | Scenario Programmer (Scenes) | Who = 17 SCENES |
v1.0.0 (2015-04-09) | Verified | switch, event |
MH200 / MH200N / MH202 scenario programmer integration, enable/disable automated schedules. |
| 18 | Energy Management | Energy Management Functions |
v1.0.0 (2011-07-15) | Verified | sensor |
Electricity, water, and gas pulse meters. Instantaneous power (W), active energy (kWh), current (mA), voltage (V) (F520, F522, 3522). |
| 22 | Sound Diffusion | Who = 22 Sound Diffusion |
v1.1.0 (2014-06-12) | Verified | media_player |
Source navigation & speaker control: Radio FM frequency step up/down, station presets, track skipping, RDS display streaming. |
| 24 | Lighting Management | Who_24_eng_PUBBLIC.doc |
v1.0.0 (2012-04-06) | Verified | light, sensor |
Legrand Lighting Management System (BMNE500, BMview). Room controllers, lux thresholds, auto-off delay timers. |
| 25 (CEN+) | CEN+ Scenario Control | CEN Frames for Scenario Scheduler |
v1.0.0 (2010-10-01) | Verified | event, device triggers |
Extended CEN protocol with up to 256 buttons/scenarios for MH200/MH200N/03565. |
| 25 (Contacts) | Dry Contact & IR State | DRY CONTACT AND IR STATE FUNCTIONS |
v1.0.0 (2010-11-04) | Verified | binary_sensor |
Dry contact interfaces & IR sensor state: State ON / IR detection (WHAT=31), State OFF (WHAT=32). BTicino 3477, F428, 3480, 4610. |
| HMAC | Gateway Authentication | Hmac Specification |
v1.1.0 (2016-08-05) | Verified | Core transport | Cryptographic challenge-response HMAC-SHA256 authentication replacing legacy OPEN numeric password authentication. |
| INTRO | OpenWebNet Architecture | INTRODUCTION Examples of Integration |
(2012-10-03) | Verified | Core protocol | Foundational architecture manual detailing frame delimiters, session separation (Command vs Event/Status), ACK/NACK signaling. |
🔍 OpenWebNet Frame Syntax Reference¶
OpenWebNet messages always begin with * and end with ##. Fields are separated by *:
1. Standard Command / Status Message¶
Example:*1*1*21## (Turn ON light at address A=2, PL=1)
2. Dimension Request (Query)¶
Example:*#4*1*0## (Query measured temperature of Zone 1)
3. Dimension Writing (Command with Parameters)¶
Example:*#16*1*#1*30## (Set volume of audio Amplifier 1 to 30%)
4. Dimension Response (Status Report)¶
Example:*#4*1*0*0215*1## (Zone 1 temperature is 21.5 °C, Heating mode)
5. Acknowledge (ACK / NACK)¶
*#*1##: ACK (Command accepted by gateway/bus)*#*0##: NACK (Command rejected, syntax error, or buffer busy)
🔌 Gateway Architecture & Hardware Profiles¶
| Model | Hardware Type | Transport | Default Port | Auth Protocol | Queue Pacing | Notes |
|---|---|---|---|---|---|---|
| MH200 | Scenario Programmer | TCP/IP | 20000 | Open password / None | 150 ms | Embedded ARM, scenario scheduler, legacy buffer limits. |
| MH200N | Scenario Programmer | TCP/IP | 20000 | Open password / None | 100 ms | Updated network interface, scenario engine. |
| MH201 | Scenario Controller | TCP/IP | 20000 | Open password / None | 80 ms | DIN-rail scenario controller. |
| MH202 | Scenario Programmer | TCP/IP | 20000 | Open password / None | 50 ms | High-speed ARM CPU, expanded memory. |
| F452 | Web Server IP | TCP/IP | 20000 | Open password / None | 150 ms | Early generation IP gateway. |
| F453AV | Audio/Video Web Server | TCP/IP | 20000 | Open password / None | 120 ms | Supports door entry and basic web control. |
| F454 | Web Server IP | TCP/IP | 20000 | Open numeric password | 80 ms | Dual bus interface, widely deployed standard DIN gateway. |
| F455 | Advanced IP Gateway | TCP/IP | 20000 | Open numeric password | 50 ms | High-throughput industrial gateway. |
| MyHomeServer1 | Modern IoT Gateway | TCP/IP | 20000 | HMAC-SHA2 (SHA-256) | 30 ms | Fast SoC, alphanumeric credentials. |
| F461 | Next-Gen DIN Server | TCP/IP | 20000 | Alphanumeric / HMAC | 20 ms | Latest generation BTicino DIN-rail server/gateway. |
| Legrand 3578 | OpenZigBee USB Interface | Serial USB | /dev/ttyUSB* |
None (Serial bypass) | 40 ms | 19200 baud, 8N1, ZigBee wireless SCS bridge. |