def to_bytes
      # set defaults
      self.sender ||= :pc
      self.receiver ||= 1

      bytes = []

      bytes.concat [0x00] * 5                               # start of command
      bytes.concat [0x01]                                   # <SOH>
      bytes.concat self.sender.to_bytes                     # Sender Address
      bytes.concat self.receiver.to_bytes                   # Reciver Address
      bytes.concat [0x02]                                   # <STX>
      bytes.concat string_to_ascii_bytes(command_code)      # Command Code
      bytes.concat command_payload_bytes                    # command specific payload
      bytes.concat [0x03]                                   # <ETX>
      bytes.concat generate_checksum_bytes(bytes[10..-1])   # Checksum bytes (4)
      bytes.concat [0x04]                                   # <EOT>

      bytes
    end
def to_bytes
      # set defaults
      self.sender ||= :pc
      self.receiver ||= 1

      bytes = []

      bytes.concat [0x00] * 5                               # start of command
      bytes.concat [0x01]                                   # <SOH>
      bytes.concat self.sender.to_bytes                     # Sender Address
      bytes.concat self.receiver.to_bytes                   # Reciver Address
      bytes.concat [0x02]                                   # <STX>
      bytes.concat string_to_ascii_bytes(command_code)      # Command Code
      bytes.concat command_payload_bytes                    # command specific payload
      bytes.concat [0x03]                                   # <ETX>
      bytes.concat generate_checksum_bytes(bytes[10..-1])   # Checksum bytes (4)
      bytes.concat [0x04]                                   # <EOT>

      bytes
    end
Returns a byte array representing this command, appropriate for sending to the sign's serial port

 @return [Array<Byte>]