# ADR-0009: Panel Semantics Are Protocol-Neutral

Status: Accepted

## Context

Home Assistant expects consistent panel-level semantics
regardless of protocol.

M1 and E27 expose panel information differently.

## Decision

Panel is a semantic concept, not a protocol artifact.

- Panel identity, version, capabilities, and health
  are normalized semantically.
- E27 does not implement M1-only concepts
  (e.g., remote programming).

## Rationale

This enables shared HA integration logic
without forcing protocol parity.

## Consequences

- Some features are protocol-specific.
- HA entities must tolerate missing capabilities.

## Scope / Non-Goals

- Does not require feature parity.
- Does not define HA entity behavior.

## References

- elkm1_lib/panel.py
