/**
 * Utility class for Modbus RTU (Remote Terminal Unit) framing.
 * Provides methods to wrap PDUs into RTU ADUs and validate incoming RTU packets.
 */
export declare class RtuFramer {
    /**
     * Builds a Modbus RTU ADU (Application Data Unit).
     * Structure: [Slave ID (1b)] [PDU (nb)] [CRC (2b)]
     *
     * @param {number} slaveId - The target slave unit identifier (typically 1-247).
     * @param {Uint8Array} pdu - The Modbus Protocol Data Unit (Function Code + Data).
     * @returns {Uint8Array} The complete RTU packet ready for transmission.
     */
    static buildAdu(slaveId: number, pdu: Uint8Array): Uint8Array;
    /**
     * Parses and validates a raw Modbus RTU packet.
     * Performs CRC verification and extracts the Unit ID and PDU.
     *
     * @param {Uint8Array} packet - The raw byte buffer received from the serial port.
     * @returns {{ unitId: number; pdu: Uint8Array }} Object containing the extracted unit ID and PDU.
     * @throws {Error} Throws if the packet is too short or if the CRC checksum is invalid.
     */
    static parseAdu(packet: Uint8Array): {
        unitId: number;
        pdu: Uint8Array;
    };
    /**
     * Predicts the total expected length of an RTU response based on the request PDU.
     * Useful for knowing how many bytes to read from a serial stream.
     *
     * @param {Uint8Array} pdu - The request PDU (the PDU sent to the device).
     * @returns {number | null} The expected length of the full ADU in bytes, or null if unknown.
     */
    static getExpectedResponseLength(pdu: Uint8Array): number | null;
}
/**
 * Utility class for Modbus TCP framing.
 * Handles the MBAP (Modbus Application Protocol) header used over Ethernet.
 */
export declare class TcpFramer {
    /**
     * Internal transaction counter.
     * @private
     */
    private static transactionId;
    /**
     * Increments and returns the next Transaction Identifier (TID).
     * Rolls over at 65535.
     *
     * @private
     * @returns {number} The next 16-bit transaction ID.
     */
    private static getNextTid;
    /**
     * Builds a Modbus TCP ADU (Application Data Unit).
     * Structure: [TID (2b)] [PID (2b)] [Length (2b)] [Unit ID (1b)] [PDU (nb)]
     *
     * @param {number} unitId - The unit identifier (typically 0xFF or 1 for TCP).
     * @param {Uint8Array} pdu - The Modbus Protocol Data Unit.
     * @returns {Uint8Array} The complete TCP packet with MBAP header.
     */
    static buildAdu(unitId: number, pdu: Uint8Array): Uint8Array;
    /**
     * Parses and validates a Modbus TCP packet.
     * Validates the MBAP header and extracts the Unit ID and PDU.
     *
     * @param {Uint8Array} packet - The raw byte buffer received from the socket.
     * @returns {{ unitId: number; pdu: Uint8Array }} Object containing the extracted unit ID and PDU.
     * @throws {Error} Throws if the packet is too short or if the Protocol ID is not 0.
     */
    static parseAdu(packet: Uint8Array): {
        unitId: number;
        pdu: Uint8Array;
    };
    /**
     * Predicts the total expected length of a TCP response based on the request PDU.
     * Includes the 7-byte MBAP header.
     *
     * @param {Uint8Array} pdu - The request PDU.
     * @returns {number | null} The expected length of the full ADU in bytes, or null if unknown.
     */
    static getExpectedResponseLength(pdu: Uint8Array): number | null;
}
declare const _default: {
    RtuFramer: typeof RtuFramer;
    TcpFramer: typeof TcpFramer;
};
export default _default;