Module error 

Error types for the kenwood-thd75 library.

This module defines a three-level error hierarchy that mirrors the library’s architecture:

1. Error — The top-level enum returned by all public API methods. It wraps the three lower-level categories below, plus radio-specific conditions like Error::RadioError (? response), Error::NotAvailable (N response), Error::Timeout, and MCP memory-related errors.

2. TransportError — Failures in the serial/Bluetooth I/O layer. These occur when opening, reading from, or writing to the serial port. A TransportError generally means the physical link is broken or was never established. Wrapped by Error::Transport.

3. ProtocolError — Failures in CAT command framing and parsing. These occur when the radio sends a response that cannot be decoded: wrong field count, unparseable field value, unknown command prefix, or a malformed frame (e.g., missing \r terminator). Wrapped by Error::Protocol.

4. ValidationError — Failures when a caller-supplied value is outside the valid range for its type (e.g., band index > 13, tone code > 49, power level > 3). These are raised before any I/O occurs, during construction of typed wrappers. Wrapped by Error::Validation.

All three lower-level error types implement From conversion into Error, so the ? operator propagates them naturally.

Enums

Error

Top-level error type for all radio operations.

ProtocolError

Errors in the CAT protocol layer (framing, field parsing, etc.).

TransportError

Errors originating from the transport layer (serial port / Bluetooth).

ValidationError

Errors raised when a user-supplied value fails validation.