/// <summary>
///     Categorizes PSEM errors by source.
/// </summary>
public enum PsemErrorCode
{
    /// <summary>Transport-level error (serial port, TCP connection, etc.).</summary>
    TransportError,
    /// <summary>CRC-16 verification failed.</summary>
    CrcMismatch,
    /// <summary>Operation timed out.</summary>
    Timeout,
    /// <summary>Protocol-level error from meter response.</summary>
    ProtocolError,
    /// <summary>Frame structure invalid (bad STP, length, etc.).</summary>
    FramingError,
    /// <summary>Invalid session or protocol state.</summary>
    InvalidState,
    /// <summary>Authentication or security failure.</summary>
    SecurityFailure,
    /// <summary>Procedure execution failed.</summary>
    ProcedureError
}